Biggest surprise position players of 2015

Let's take a look at some of my top surprise performers of 2015. We'll focus on position players and then look at pitchers next week.

David Peralta, Arizona Diamondbacks

Because he plays for the Diamondbacks, Peralta gets no attention. When we talk about the Diamondbacks, we usually talk about Paul Goldschmidt or maybe mention that A.J. Pollock has had a terrific season or roll our eyes over something Dave Stewart has done or said. But the D-backs have the same record as the Nationals and Peralta has been a big reason, hitting .299/.366/.516 with 12 home runs and a league-leading eight triples.

Peralta's story is a good one. The Cardinals originally signed him out of Venezuela in 2004 as a pitcher. He pitched at Rookie-level Johnson City in 2007, hurt his shoulder and disappeared for four years. He doesn't show up again until 2011, when he hit .392 for Rio Grande Valley of the independent and now-defunct North American League. In 2012, he hit .332 for Wichita of the independent American Association. In 2013, he was hitting .352 for Amarillo in the same league when the Diamondbacks signed him and sent him to Visalia of the Class A California League, a soon-to-be 26-year-old with, what, zero chance of reaching the big leagues?

Less than a year later he was in the big leagues. Give credit to Diamondbacks scout Chris Carminucci for finding Peralta.

"€œEvery independent league player brings something to the clubhouse: They've failed,"€ Carminucci told Fox Sports' Jon Paul Morosi last year. "€œIn this game, you have to learn how to fail and get back up and fight. David in particular has done that, but that's true of these other guys, too. And from the moment he walked into that clubhouse last year, everyone had instant respect for him, because he came all the way back."

Logan Forsythe, Tampa Bay Rays

Forsythe has a much different background from Peralta: The 48th overall pick in 2008 by the San Diego Padres, he reached the big leagues in 2011 but was eventually displaced at second base by Jedd Gyorko and traded to the Rays after the 2013 season. As a platoon second baseman in 2014, he hit just .223/.287/.329 and owned a career .235 average in more than 1,000 major league plate appearances.

Maybe he's figured things out or maybe 2015 will be a career season, but Forsythe is hitting .279/.360/.427. His 4.4 WAR ranks third among all second basemen, behind only Jason Kipnis and Ian Kinsler. It's been a bunch of little things that have helped Forsythe put up improved numbers: He's walking a little more, striking out a little less and has good defensive metrics. That said, in digging into some of his other metrics, nothing stands out as being much different, things such as line-drive rate or chase percentage on pitches out of the zone. He's hitting the ball a little more often to center field and less to right field, so maybe he's simply squaring up a few more pitches.

Matt Duffy, San Francisco Giants

I wrote about Duffy a few weeks ago. Nobody expected this, even the Giants. He's hitting .304/.341/.459 with 10 home runs and 59 RBIs, hitting second or third for the Giants since late June. Remember, the Giants had signed Casey McGehee -- coming off a 1.1 WAR season with the Marlins -- to replace Pablo Sandoval at third base. Duffy soon replaced him in the lineup, a remarkable rise for a kid who never hit a home run in college.

Brandon Crawford, San Francisco Giants

Crawford's surprise factor is a little different from the first three guys, considering he has two World Series rings as the team's starting shortstop. From 2012 to 2014, Crawford was very consistent at the plate, just not especially effective: He hit between .246 and .248 each year, with OBPs in the low .300s and not much power. This season, however, he's added power to his game and, combined with his Gold Glove-caliber defense, has become one of the best all-around players in the National League. He's hitting .270/.330/.489 with 19 home runs and 75 RBIs, hitting .324/.383/.541 with runners in scoring position. Your NL position player leaders in WAR:

Bryce Harper: 7.6

Paul Goldschmidt: 6.9

A.J. Pollock: 5.9

Brandon Crawford: 5.8

Anthony Rizzo: 5.7

Buster Posey: 5.5

Here's a good breakdown of some of the changes Crawford has made at the plate, where he lowered his hands a bit and started using his lower body a little more forcefully. Always a decent hitter against fastballs, he's hitting .320 and slugging .573 against them in 2015. On top of that, he's tied with Andrelton Simmons for the most defensive runs saved among shortstops. He's going to be near the top of a lot of MVP ballots and that's the surprise factor.

Mark Teixeira, New York Yankees

Just to be clear: Even aside from the injuries in 2013 (when he played just 15 games) and 2014 (123 games), this was a player in decline. His OPS totals since 2008: .962, .948 (after moving into Yankee Stadium), .846, .835, .807, .609, .711. And in 2015 ... .912. Of course.

Some of that decline came as a result of Teixeira becoming one of the most shifted-against hitters in the league. Some was aging. Some was injuries. His preseason ZiPS projection had him hitting .236/.326/.433 and worth 1.5 WAR. He's hitting .257/.359/.553 with 31 home runs and has been worth 3.9 WAR. The MVP talk is silly but his rejuvenation at age 35 is certainly a major reason the Yankees are a half-game up in the AL East.

Alex Rodriguez, New York Yankees

But it's Teixeira's teammate who takes honors as my biggest surprise of the 2015 season. Back in spring training, I think the optimistic view would have had him serving primarily as a platoon DH against left-handed pitchers. You wondered how eager Yankees manager Joe Girardi was to get A-Rod back in the lineup. The team had Carlos Beltran, who would need some games at DH, and had acquired Garrett Jones as a possible left-handed part of a platoon. Not to mentioned A-Rod was turning 40 and hadn't played much baseball the past two seasons (no games in 2014 because of his suspension and just 44 games in 2013).

He's hitting .262/.368/.501 and the skeptics have probably earned the right to question him. But remember that he had hip surgery in 2013, had an entire season to rehabilitate it, and is the healthiest he's been in years. Hey, this is an all-time great hitter. He's a smart hitter. Maybe we should have expected more. He's seventh in the majors in walk rate and power is actually something that doesn't necessarily fall off much as you age. Still, nobody saw this coming. Yes, it's hard to root for A-Rod and the Yankees, but if he's in the postseason that will be great October drama.