Free agency is always a gamble, but the class of 2008 might make bookmakers in Las Vegas nervous.
Of the first 78 players to move to different teams, 48 played less than 50 percent of the downs last season for their previous squads. Over the past three decades, the NFL has developed into a league of role players and situational substitutions. So those figures aren't unusual.
Still, it's a gamble to spend millions of dollars for players who aren't on the field half the time. Some teams are taking a chance that backups can convert to starters. Others are gambling that players can switch positions and live up to their massive contracts.
The stakes are high, but teams have to take gambles to improve. Here are 10 of the biggest and most interesting gambles less than two weeks into the hottest free-agency period in NFL history.
1. Transforming DEs into LBs: With roughly a third of the league using some form of the 3-4 defense, three teams gambled on defensive ends they hope to convert into pass-rushing linebackers.
The New York Jets put their money on Calvin Pace, who was drafted as a 4-3 defensive end but took on some linebacker duties in Arizona because of injuries to Bertrand Berry and Chike Okeafor. Pace received a staggering six-year, $42 million deal even though he's never had more than 6½ sacks in a season.
To replace him, the Cardinals are gambling $4.4 million a year on
Travis LaBoy, a defensive end with Tennessee. The Cincinnati Bengals, who will start to use a hybrid 3-4 defense, spent $5.9 million a year on Antwan Odom, who had a career-high eight sacks last season in the Tennessee Titans' 4-3.
2. Exotic nose (tackle) jobs: For the past couple of years, the San Francisco 49ers, Cleveland Browns and Jets have tried the 3-4 but have been in the bottom 10 in rushing yards allowed. The key to any 3-4 defense is the nose tackle, who needs to draw double-team blocking to free up linebackers to make plays. The Jets and Browns didn't fool around in making trades, but it's not 100 percent certain how their new players will adjust to the 3-4 scheme.
The Browns and Jets, respectively, are gambling that Shaun Rogers and Kris Jenkins can convert from Pro Bowl defensive tackles in a 4-3 into 3-4 nose tackles. Both players have the size and power to make the transition. At times, both players have been unblockable.
The 49ers, meanwhile, wagered $7.5 million a year that former Bengal Justin Smith can convert into a 3-4 defensive end. Smith was known for his relentless effort even though he wasn't considered much of a threat for quarterback sacks. With Bryant Young retiring, the 49ers want Smith to be their feature defensive end in the 3-4.
3. Falcons betting on the long run: Nobody argues that former San Diego Chargers backup Michael Turner was the best running back in free agency. He's big. He's fast. His nickname is The Burner. When LaDainian Tomlinson needed a breather, Turner would strike fear in defenses, slamming his 237-pound body into the line and breaking long runs.
The Atlanta Falcons didn't blink in giving him a six-year, $34.5 million contract and a $15 million signing bonus. But banking on Turner as a starting running back is still a gamble. He's never had more than 80 carries in a season and he's never played more than 12 percent of the offensive snaps in a season. The Raiders gambled that Jets backup LaMont Jordan can be the full-time starter, and that didn't work out. The Vikings gambled on Chester Taylor and succeeded.
4. Third team's a charm for Woody? For the Jets, signing former Pittsburgh Steelers standout lineman Alan Faneca to an $8 million a year contract wasn't a gamble. Faneca is one of the best guards in football and should help left tackle D'Brickashaw Ferguson and center Nick Mangold play at a higher level.
The Jets' gamble was the $25.5 million contract given to Damien Woody. He was drafted as a center by the New England Patriots and signed with the Detroit Lions as a guard. He's been to the Pro Bowl with the Patriots, but things didn't work out all that well for Woody as a guard with the Lions.
Last summer, figuring Woody was going to be a potential backup, the Lions restructured his contract and allowed him to hit free agency this winter. Late in the season, they tried him at right tackle and he did surprisingly well. The Jets are gambling $5.1 million a year that Woody can be a top right tackle.
5. The Jets' future is now: Staying with the Jets: They are gambling against the biological clock in free agency and trades. Most teams try to add younger players when they sign high-priced free agents or make trades. The Jets are one of the few teams willing to add some age. Faneca is 31 and Woody is 30. Fullback Tony Richardson is 36 but is coming off a Pro Bowl season, while 34-year-old cornerback Ty Law is coming in for a visit this week. The Jets aren't worried about building for the future. They want to win now.
6. Risky cornerback promotions? It's a gamble to draft a cornerback in the first two rounds and put him on the field as a starter. Quarterbacks tend to pick on the rookie and keep throwing at him until he shuts down a receiver. Rather than wait for the draft, some clubs sign other teams' third cornerbacks as potential starters.
The New Orleans Saints gave Patriots third cornerback Randall Gay a four-year, $13.55 million deal. The second-best cornerback contract in free agency this offseason -- a six-year, $36.1 million deal -- went to new Jacksonville Jaguars defender Drayton Florence, a longtime Chargers starter who finished as the third corner last season.
Reeves and Florence finished in the top eight among cornerbacks in the "most passes completed against" category, according to Stats Inc.
7. Another round of Broncos revisions: Denver Broncos coach Mike Shanahan gambled and lost last season when he changed six of his top 10 defensive linemen.
The cost wasn't too bad. Bailey was the costliest at $3.5 million a year, while
the others signed for less than that. Shanahan has to gamble on free agency to fix his defense. D.J. Williams and Elvis Dumervil were the only drafted Broncos defenders to play more than 60 percent of the snaps last season. Shanahan hopes his moderately priced fixes repair the defense.
8. Bills rebuild middle with spare parts: Marcus Stroud was the anchor of the Jaguars' defense for seven seasons. He gave the line personality, and running up the middle against the Jaguars used to be impossible. But the Jaguars were willing to trade him because they thought he wasn't the same player after microfracture surgery on his ankle. The Bills hope they were wrong.
Stroud and Spencer Johnson, formerly of the Minnesota Vikings, were acquired to toughen up the middle of the Bills' 4-3 defense. The Bills finished 25th in the league in run defense, allowing almost 4.4 yards per carry. Coach Dick Jauron hopes Stroud can regain his status as the anchor to his defense.
9. Raiders take a flier on Walker: There is no middle ground on thoughts about Javon Walker. Walker was considered a Randy Moss-type talent with the Green Bay Packers; the Broncos acquired him in a trade to revamp their offense. But recently Shanahan feared Walker's knee might be getting closer to needing microfracture surgery in the next couple of years, so the two sides parted ways.
Raiders owner Al Davis gambled $55 million over the next six years that Shanahan was wrong. Davis hopes Walker will not only be a big receiving target for quarterback JaMarcus Russell, but also a deep threat. Confident in his move, Davis handed Walker an $11 million check as a signing bonus.
10. Titans welcome Crumpler, the return of The Freak: The Titans felt they were top-heavy in drafted players who were heading into free agency and said goodbye to five 2004 draft choices taken from Rounds 2-5 (these players were between the ages of 24 and 26). To fill in for some of the losses, the Titans are gambling on aging Pro Bowl starters who have had recent injury histories.
The Titans added former Philadelphia Eagles defensive end Jevon Kearse -- for his second stint in Tennessee -- and former Falcons tight end Alge Crumpler. The Titans are gambling that Kearse and Crumpler, who have combined for seven trips to the Pro Bowl, will find the fountain of youth and take advantage of their new opportunities in Nashville.
Senior writer John Clayton covers the NFL for ESPN.com.