What must go right: For the first time since 1995, the Angels' closer will be somebody other than Troy Percival. Francisco Rodriguez, the heir apparent since he blew away opponents in the 2002 postseason, has impeccable credentials and stuff, and there's no reason to think he can't do the job. But sometimes transitions like this don't go as seamlessly as expected -- see Octavio Dotel, Astros, 2004 -- and the Angels also must promote Scot Shields or Brendan Donnelly into the primary setup role that K-Rod is vacating.
What could go wrong: The Anaheim lineup should be tough and deep and efficient, but it is constructed heavily on the broad shoulders of Vladimir Guerrero. Take Gary Sheffield away from the Yankees, and they would survive; remove David Ortiz from the Red Sox, and Boston would still find a way to score runs. But if Vlad doesn't hit for some reason, or if he's hurt, the Angels' attack would suddenly look very thin; no player this side of Barry Bonds is more important to his team's offense than Guerrero is to the Angels. They've got to keep him healthy and on the field.
The X-Factor: Rookie third baseman Dallas McPherson comes to the majors amid great expectations. He could be the difference between the Angels' having a good offense and having a great offense.
Numerically speaking: Bartolo Colon went 6-8 with a 6.38 ERA before the All-Star break, and 12-4 with a 3.63 ERA after the break.
What must go right: The Orioles must find some pitching, something they failed to during the offseason. In particular, they need Sidney Ponson to lead the staff, as he did in the second half of last year after Ray Miller took over as pitching coach. Ponson's ERA in the last three months was 3.21, 5.82, 3.50. (It does not bode well that Ponson spent part of his winter in jail for an alleged altercation). Erik Bedard went 6-10 with a 4.59 ERA and the Orioles need him to come quickly.
What could go wrong: The acquisition of Sammy Sosa was the one major move made by the O's during the offseason, so the team's renewed hope is built on an aging slugger who has been in clear decline the last three seasons. Maybe Sosa will be invigorated, but if he plays badly early and the Orioles struggle, it could get ugly in a hurry in Baltimore.
The X-Factor: The presence of the Washington Nationals will be an interesting dynamic because Orioles owner Peter Angelos strongly fought the placement of that team and will be preoccupied by their performance and attendance. Any early success for Washington may spur Angelos into action -- perhaps into a shakeup of the Orioles' roster, or a change in manager, something Angelos has never done in the midst of a season.
Numerically speaking: Eleven of the Orioles' 24 games in April will be against the Yankees and Red Sox.
What must go right: Pedro Martinez and Derek Lowe each left amid some ugliness and bad feelings on all sides. But as spring training opens, it really doesn't matter whether Martinez's departure was all about money or whether Lowe might have applied himself a little more seriously; what matters is that the Red Sox have to replace two veteran pitchers who combined to win 108 games over the last three years (regular season and postseason combined). Boston signed Matt Clement to a three-year deal, and no one doubts that Clement has great stuff -- he had 190 strikeouts in 181 innings last year, and has averaged almost a whiff per inning during his career. But there are questions about whether Clement can make the adjustment to the American League, and how he'll handle the pressure of playing in the northeast. The Sox must have a good year from him.
What could go wrong: Boston is an older team -- 19 members of their 40-man roster are over 30 years of age. Whether it's back trouble for Trot Nixon or David Wells, it's a group that may be more susceptible to injury.
The X-Factor: Since the new Red Sox management took over, it has wanted to change the clubhouse culture, and now the days when stars might stray onto their own separate agendas might be gone for the foreseeable future. The Red Sox belong to the likes of Jason Varitek and Nixon, which ensures that the great chemistry that helped the Red Sox through the postseason last year will continue into 2005. Clubhouse culture was a great unseen weapon for the O'Neill-Martinez Yankees of 1996-2001, and similarly, this could be crucial for Boston as it tries to repeat.
Numerically speaking: Wade Miller racked up 45 victories in his last three full seasons, before being felled by rotator cuff problems last year. He has ability to help tip the balance of power between the Yankees and Red Sox if he makes a full recovery by late in the season.
What must go right: The White Sox hit a lot of homers last year, but GM Kenny Williams has restructured the offense, dealing away Carlos Lee for Scott Podsednik and signing Jermaine Dye and A.J. Pierzynski. The White Sox should have a deeper offensive attack, but they've got to hope the newcomers and the increased team speed make up for the absence of Lee's big bat.
What could go wrong: The White Sox are built around their starting rotation of Mark Buehrle, Freddy Garcia, Jose Contreras, Jon Garland and Orlando Hernandez. Buerhle went 16-10 last season, Garcia was 9-4 for the White Sox, and the other three guys can be effective. But it's well within the realm of possibility that this group won't be as good as the White Sox need it to be, even in the balanced AL Central -- and that would be a disaster.
The X-Factor: Contreras went 5-4 with a 5.30 ERA, and Garland was 12-11 with a 4.89 ERA. They need to be better than that.
Numerically speaking: Aaron Rowand is an old-school, swing-away type of player who will be vital to the White Sox offense this year -- he had more than twice as many extra-base hits (64) as walks (30), and batted .310.
What must go right: Slowly, the Indians have built up the depth on their starting staff. But they've got to get more out of Cliff Lee, whose slide last season coincided with the Indians' fall from contention. They've got to hope that Kevin Millwood does not flounder in making the switch from the NL to the AL. And they've got to hope that Bob Wickman holds up as closer.
What could go wrong: Wickman emerged after the All-Star break to create some stability within a bullpen that had become infamous for its failures. Consider that he was 13 of 14 in his save chances, while the rest of the staff converted on only 19 of 46 chances. So long as the likes of David Riske and Rafael Betancourt are used in middle relief, it seems, they are serviceable. But Wickman, with his long history of injuries, is the key link.
The X-Factor: The Indians have a solid core of offensive weapons, and they've got a lot of depth, with players such as Juan Gonzalez vying for jobs. In what will probably be a competitive but mediocre division, it's not out of the realm of possibility that Cleveland could slug its way to a division title.
Numerically speaking: The Indians ranked fourth in the AL in batting average (.276), third in on-base percentage (.351), fifth in runs scored, second in doubles -- and this is a young team that is getting better.
What must go right: Some of the newest acquisitions played better than expected last year, helping the Tigers make a significant improvement. Shortstop Carlos Guillen was talked about as one of the league's primary impact players, Ivan Rodriguez gave the Tigers a jolt and Nate Robertson emerged to win 12 games. The Tigers have to get similar contributions this year, and have other newcomers -- Magglio Ordonez, Troy Percival -- make an impact.
What could go wrong: Jeremy Bonderman pitched strongly down the stretch, Mike Maroth cut his ERA by almost a run and a half, and Jason Johnson had some decent moments. If these guys aren't more consistent, the Tigers have no shot at staying in the division's lead pack.
The X-Factor: Ordonez was one of the game's great right-handed hitters before he hurt his knee last year, and if he rebounds, he'll be an RBI machine. But if he never is fully healthy again, it's possible that his contract -- $75 million for five years, maybe another $30 million -- could haunt this mid-market team for many, many years. The Tigers are not in a position to afford a $15 million DH.
Numerically speaking: Bonderman had a 2.93 ERA in his last 10 starts of last season, allowing just 53 hits and striking out 67 in 67.2 innings.
What must go right: They are in rebuilding mode, again, after the horribly disappointing start of 2004 and the subsequent trade of center fielder Carlos Beltran. They've got to get a lot of good young parts in place, around pitcher Zack Greinke, before they will contend in this division. If you are a young player looking to establish yourself in the majors -- like the Royals' Angel Berroa, John Buck, Mark Teahan and David DeJesus -- this is about as good a place to be as any.
What could go wrong: The Royals will be all about development. Injuries to any of the young guys will slow that process down.
The X-Factor: Mike Sweeney is the organization's signature guy, and for a team with so many young players, he's an important piece of stability. His name will be a constant in the rumor mill this year.
Numerically speaking: Greinke didn't turn 21 until October, and yet in his first season in the majors, he walked only 28 in 145 innings, with 100 strikeouts, and a 3.97 ERA. Those are hints of someone who is going to be very successful for a very long time.
What must go right: Corey Koskie and Cristian Guzman are gone and the left side of the Twins' infield will be new, with Michael Cuddyer taking over at third and a trio of candidates vying for shortstop. At the very least, the newcomers must become proficient defensively; the ability to catch the ball has been the common denominator for the Twins' success over the last few years. Minnesota has not always had a dynamic offense or pitching depth, but the Twins have made plays in the field.
What could go wrong: Like most small- and mid-budget teams, the Twins are not well suited to deal with unexpected problems. They are counting on Joe Mauer to come back from knee trouble and be a productive player; they signed Brad Radke to a multi-year deal assuming he will continue to win games; they have to assume that first baseman Justin Morneau can bear a large burden of the offense. Any major setback would be mitigated only by the fact that they play in the AL Central, a division loaded with similarly flawed teams.
The X-Factor: Kyle Lohse is talented and he's had some success, winning 40 games ... But for some reason, he has not put it all together yet; if he does, the Twins' rotation will be formidable and four-deep, to go along with a solid bullpen. If he doesn't, it will be a problem.
Numerically speaking: Shannon Stewart is the only projected starter, among the position players, who is older than 30.
What must go right: It's all about maintenance for the Yankees in spring training, just trying to get to April without significant injury questions developing. They have the potential for a monster regular season, because the addition of Randy Johnson fills the one glaring need the Yankees had in 2004. Now they have a deep rotation, arguably the best bullpen, a powerful offense, a serviceable defense. Because of their depth, they are destined to crush many small and mid-market teams this summer.
What could go wrong: It's a team loaded with ancients, from the 41-year-old Johnson to the 36-year-old Gary Sheffield; Alex Rodriguez turns 30 this year and he's the youngest starting position player. The Yankees have enough depth to sustain a few injuries, but if Johnson goes down, his absence would affect everybody -- and the organization simply is not in a position to make up for injuries with its farm system.
The X-Factor: Jason Giambi will be under more scrutiny this season than any player since Jackie Robinson in 1947 (and for reasons, obviously, that cannot be compared). If he somehow returns to being a productive player -- say 25 homers, a .390 on-base percentage -- he would give the Yankees a ridiculously deep lineup. But some in the Yankees' organization will be greatly surprised if that happens.
Numerically speaking: The Yankees' staff ERA last season was 4.69 -- the team's worst ERA since 1930, with the exception of the 2000 season (4.76), when the club's record was bloated by a rash of late-season blowout defeats.
What must go right: From 2000 through 2004, the Athletics won nearly two-thirds of their games when Tim Hudson, Mark Mulder or Barry Zito started; when anybody else started, the Athletics' winning percentage was under .530. Now Hudson and Mulder are gone, replaced by talented young pitchers who don't have much of a track record in the majors. Unless one or two out of the trio of Danny Haren, Dan Meyer and Joe Blanton repeat the instant success that characterized the Big Three, Oakland will struggle to reach 90 victories.
What could go wrong: Oakland should have its best offense since the departure of Jason Giambi, as Keith Ginter takes over at second base, Jason Kendall becomes the everyday catcher and OBP-machine Nick Swisher assumes a greater role. But like the rotation, the bullpen is flush with talent and lacking in experience. Kiko Calero, Juan Cruz, Jairo Garcia and Octavio Dotel all have the stuff to be overpowering; whether or not that happens remains to be seen.
The X-Factor: Zito must be a leader on this staff, and he's coming off the worst season of his career -- 11-11, with a 4.48 ERA. Rich Harden has the stuff and the makeup to be the ace, but Zito will have to perform to take pressure off the other members of the rotation. If he struggles, then it's possible he'll wind up with another team by the July 31 trade deadline.
Numerically speaking: Starters No. 2 through 5 in this rotation have 22 career victories in the majors.
What must go right: The addition of Adrian Beltre and Richie Sexson beefs up a poor offense, and now the Mariners must find some solutions on a pitching staff full of question marks; there is not one sure-thing in the rotation or bullpen. Can Jamie Moyer bounce back from a season in which he allowed 44 homers? Can Joel Pineiro and Gil Meche rebound? Will Rafael Soriano be the force the Mariners expect him to be?
What could go wrong: No one doubts that Sexson can produce when he's healthy. But executives around both leagues were surprised Seattle invested so much in a player who missed most of last season because of an injury incurred with an action inherent to the game -- swinging a bat. The Mariners are convinced Sexson has healed, but every time he checks his swing in spring training and early in the season, club executives will be cringing a bit.
The X-Factor: Bobby Madritsch came up last season, at age 28, and pitched extremely well, showing great poise and a bulldog mentality as he faced AL West contenders in September. He looked like the real deal, going 6-3 with a 3.27 ERA -- and Seattle needs him to be legit, rather than a late-season flash.
Numerically speaking: The Mariners ranked 28th in the majors in homers, with 136, one more than the worst two teams (Milwaukee and Arizona, with 135). Beltre and Sexson hit a total of 93 in their last full seasons -- Beltre, with 48 last year, Sexson with 45 in 2003.
What must go right: They need to find better starting pitching; they need some of their young position players to mature as hitters; they need more talent; they need about two million more fans to attend; they need the Red Sox and Yankees to move into another division. All of that probably won't happen in 2005.
What could go wrong: Lou Piniella's raging competitiveness can drive a mediocre team into surprising success -- and it can also bury a struggling team. There were rumblings last season that he was dissatisfied with the direction of the team, and if the Rays fail to show progress early this year, Piniella may finally be driven over the edge, and his unhappiness could become a problem.
The X-Factor: B.J. Upton is one of the top prospects in the game with transcendent offensive skills, but he is error-prone at age 20 and Piniella won't ever have the patience to watch a mistake-prone shortstop. Where Upton plays -- maybe he'll remain at shortstop and open the year in Triple-A, or move to third or the outfield -- will have an impact on other choices the Devil Rays make in the next couple of years.
Numerically speaking: Tampa Bay had fewer pitches per start than any AL team, and averaged a little better than 5 1/3 innings per outing. That has to improve for the Rays to become competitive.
What must go right: The Rangers had the ultimate smoke-and-mirrors starting rotation last year -- only Tampa Bay's starters had fewer innings than those from the Rangers (901), and the Texas rotation ERA was 5.16, 11th in the AL. Texas managed to overcome all that, somehow, with great bullpen work and the relentless effort of the position players. It is a fragile formula that would be very hard to repeat, and the Rangers must have better starting pitching -- and they didn't do much to upgrade the rotation in the offseason, despite their efforts to do so.
What could go wrong: Texas managed to rank fourth in the majors in runs scored despite ranking 21st in on-base percentage. It's possible that the offense could take a step back. It's possible that the bullpen won't be as good as it was last year. It's possible that Texas will not be as dominant at home as in 2004. The Rangers had a lot of things fall into place and contended last year, and it would seem to be well within the realm of possibility that they could take a step back this year.
The X-Factor: Maybe Chris Young will take a step forward. Maybe Chan Ho Park will shock. Maybe Kenny Rogers will turn out to be his generation's Tommy John, winning into his 40s. But the rotation needs some big dogs.
Numerically speaking: The cumulative record for the starters was 55-58. The bullpen went 34-15, with a 3.46 ERA; the manner in which Buck Showalter and Orel Hershiser ran this group last year might be the best thing they did.
What must go right: Toronto is probably still a year or two away from seriously challenging the big guns at the front of the AL East. To make some strides immediately, the Jays need Roy Halladay to rebound to his 2003 form, and a couple of their young pitching prospects to mature -- in particular, Dave Bush, who had some nice outings in August, and Brandon League, a hard-throwing reliever.
What could go wrong: Carlos Delgado became an albatross for the small-budget Jays, because of his $17 million salary; his presence prevented Toronto from making other moves. But the guy also flat-out produced -- eight straight seasons of 30 or more homers, nine straight seasons of 90 or more RBI. Amid a most inconsistent lineup of inconsistent young hitters, Delgado often held the offense together. Now he is gone, putting more pressure on Vernon Wells (without protection from Delgado), more pressure on newcomer Corey Koskie, more pressure on Shea Hillenbrand, who is among those expected to replace Delgado at first base.
The X-Factor: Right fielder Alex Rios gets scouts excited with his raw tools, and they can project good things from him. In 426 at-bats last year, he had 24 doubles, seven triples, 15 stolen bases, a .286 average -- and just one home run.
Numerically speaking: In 2003, Halladay went 22-7, and the Jays finished at 86-76. Last year, Halladay was 8-8, and Toronto's record was 67-94.
Buster Olney is a senior writer for ESPN The Magazine. His book, "The Last Night of the Yankee Dynasty," is a New York Times best seller and can be ordered through HarperCollins.com.