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Back in the late 1980s, the NFL waded into the free agency era with a system known as Plan B free agency.

Because teams had been used to controlling the playing future of their players, the NFL needed a bridge to get into total free agency. The Plan B system allowed teams to protect 37 players. Unless a general manager screwed up, good players weren't going to hit the free agent market.

Fast forward to 2007. The salary cap has ballooned to $109 million so every team should have the means to keep its prized possessions. Championships can't be built on free agency alone. Of the 126 unrestricted free agents that hit the market, only 77 received multiyear contracts -- with 36 getting at least $3 million a year.

Call it Plan B-Plus free agency.

The 49ers planned for a year to have an active offseason, hitting the draft and free agency for a number of impact players. They signed five potential starters out of free agency, traded for wide receiver Darrell Jackson and had one of the best drafts. Sensing a little that the biological clock might be ticking on a core group of players who won three Super Bowl rings, the Patriots were the surprise team of the offseason. New England added four wide receivers, including Randy Moss, and signed linebacker Adalius Thomas.

Training camps open in about eight weeks and only the long-drawn out Trent Green trade is left in terms of significant moves. With that in mind, it's time to grade the 10 top acquisitions of the offseason.

Nate Clements

Cornerback San Francisco 49ers Profile

2006 SEASON STATISTICS Tot Solo Ast FF Sack Int 72 56 16 2 0 3

1. 49ers sign cornerback Nate Clements: Clements' agent, Todd France, created some nice headlines by revealing the 49ers gave Clements an eight-year, $80 million contract, making him one of the richest defensive players in football. While the actual payout might not allow Clements to top the deal of Champ Bailey of the Broncos, the acquisition should have just as much impact. With Clements and Walt Harris and Shawntae Spencer, coach Mike Nolan can match up against the other teams in the three-receiver crazy NFC West. Clements can take the opponent's top receiver and let Harris and Spencer take the other two. After finishing 26th and 32nd against the pass under Nolan the last two years, it's not out of the question for the 49ers to be in the top 10 against the pass.

2. Patriots sign linebacker Adalius Thomas: Giving Bill Belichick one of the NFL's most versatile defenders is dangerous. Belichick is the best coach in the NFL at finding a player's strength and using it. Thomas, who grabbed a $35 million contract, gives Belichick an unlimited bag of tricks. For the Ravens, Thomas had 28 sacks over the past three years. He can rush the quarterback with his hand on the ground or he can blitz from the linebacker spot. He's also decent in pass coverage. At one of the Patriots' offseason camps, Belichick had Thomas playing the inside linebacker position, giving him a shorter route to rush the quarterbacks on the run.

3. Seahawks sign defensive end Patrick Kerney: Pass-rushers rarely hit the free agent market. Kerney voided the final two years of his deal with the Falcons and hit the open market. Because Kerney's contract wasn't expiring, the Falcons couldn't use their franchise tag on him. Kerney comes to a Seahawks team in desperate need of an additional pass rusher. Over the past three years, the Seahawks have undergone major changes in the secondary. During their Super Bowl year in 2005, the Seahawks patched the second and third cornerback spots with free agents Kelly Herndon and Andre Dyson. They now have given way to youngsters Kelly Jennings and Josh Wilson along with veteran Marcus Trufant. Young corners need a consistent pass rush to survive. If they're left in coverage for too long they'll get burned. With Kerney on board, Seahawks defensive coordinator John Marshall can play all kinds of games with his pass-rushers. He has Kerney, with his 10-sack potential on one side, and Bryce Fisher on the other. He can blitz Pro Bowl linebacker Julian Peterson. The Seahawks have the makings of a top-15 defense.

4. Patriots acquire wide receiver Randy Moss: Moss isn't the 100-catch receiver of his Vikings days. It takes him longer routes to get to full speed and when he isn't the main target, he meanders on routes. And if for some reason a pass is thrown low, he might not try as hard to reach it. Still, Moss should be destined for at least a 10-touchdown season working with Tom Brady. Moss was the headliner on the 2005 offseason with his trade to the Raiders, which appeared to be a steal for the Raiders at the time. Two years of losing discouraged him. Moss took a pay cut from $10 million to $3 million for a chance at a Super Bowl ring. All Brady has to do is send Moss on go routes, throw the ball high and wait for Moss to snatch it from the air.

Willis McGahee

Running Back Baltimore Ravens Profile

2006 SEASON STATISTICS Rush Yds TD Rec Yds TD 259 990 6 18 156 0

5. Ravens acquire running back Willis McGahee: McGahee might not have all the accomplishments of his predecessor, Jamal Lewis, but he allows Brian Billick to take the Ravens' offense into a new direction. Lewis has limitations. He was a powerful, unstoppable runner, but he wasn't much of a receiving threat. Plus, he did his best work with a fullback. McGahee allows the Ravens to move more into a spread offense and he's excellent out of one-back sets. The Ravens will let him try to catch the ball more than he did in Buffalo. Over the past couple of years, the Ravens used a lot of two- and three-tight end formations. McGahee gives the team younger legs and a chance to expand the offense.

6. Jets acquire running back Thomas Jones: Anytime you can acquire a 1,200- or 1,300-yard back in his prime, you help your offense. Despite going to the playoffs, the Jets ranked 25th on offense and averaged only 19.8 points a game, below playoff standards. Eric Mangini, before his days of making cameos on "The Sopranos," went week-to-week looking for a hot running back and couldn't find one. Jones' specialty is making one cut and going behind a zone blocking scheme. He's an excellent receiver on third downs. Plus, quarterbacks love him because he's a good blocker on passing situations.

7. Broncos sign running back Travis Henry: As he proved with Reuben Droughns, Mike Anderson and others, Mike Shanahan can take an unproven back or a converted fullback and turn them into a 1,200-yard runner. His system for running is that good. In acquiring Henry, Shanahan gets a three-time 1,200-yard plus runner who is only 28. With a young quarterback, Jay Cutler, having the luxury of running is important. It takes the pressure off Cutler and gives him easier second and third downs to convert. Henry should work perfectly in the Broncos one-cut, zone blocking scheme.

Matt Schaub

Quarterback Houston Texans Profile

2006 SEASON STATISTICS Att Comp Yds TD Int Rat 27 18 200 1 2 71.2

8. Texans acquire quarterback Matt Schaub: This is no knock on Schaub's ability. In preseason and in his limited role with the Falcons, Schaub earned the right to be considered the next starting quarterback in the league. The problem for Schaub is the surrounding cast. Except for the aging Ahman Green (an offseason addition), Schaub plays behind the same offense that brought down David Carr. The Eric Moulds trade didn't work out, so Schaub has to make the best out of Kevin Walters on the other side of Andre Johnson.

9. Texans sign running back Ahman Green: The flag goes against the Green Bay Packers. They march back 10 yards for losing a potential 1,000-yard runner whom Brett Favre idolized. Not only did the Packers lose the running consistency of Green, but they lost his leadership. Now, Favre has to regroup with Vernand Morency and rookie Brandon Jackson. It will take time for the Packers running game to get back to full speed. Favre needs it now.

10. Rams sign wide receiver Drew Bennett: Somehow, Vince Young, through pure will, pulled off an 8-5 stretch run that enabled him to win Rookie of the Year honors and put the team at .500. Losing Bennett to the Rams won't help. Bennett was a tall target who helped move the chains. He goes to the Rams as a quality end zone threat and a possession receiver. Young lost two of this top three receivers -- Bennett and Bobby Wade. Young lost Travis Henry and might lose unrestricted free agent Chris Brown. If Brown also leaves, Young is without two of his three top running backs from last season. The Titans were hoping to move forward with their offense, not backward.

John Clayton is a senior writer for ESPN.com.