2012 NFL Free Agency: 4 Players Who Can Instantly Improve Struggling Franchises

As we approach the start of the NFL's free agency period on March 13, there are already several players who have separated themselves as the best available in this year's class.

The following is a list of four guys who have the ability to single-handedly turn around aspects of a struggling franchise. They are impact players who won't come cheap and could be off the board early.

Here are the four guys I think will have the most immediate impact for their next team and could go a long way to help struggling franchises.

Vincent Jackson

Vincent Jackson is a legitimate No. 1 receiver, and any team in need of a go-to guy at wideout would get their money's worth by landing him.

At 6'5" and 230 pounds, Jackson has elite size to go along with good speed and phenomenal hands. He can be both a deep threat and a possession guy. Thanks to his bulk, he's not afraid to go over the middle or mix it up in the air when going deep. 

Jackson is a two-time Pro Bowler who finished the 2011 season with 60 receptions for 1,106 yards and nine touchdowns. During his seven-year career, he has 272 catches for 4,754 yards and 37 touchdowns. When you consider he has been sharing targets with tight end Antonio Gates, you realize his numbers could have been much higher.

The San Diego Chargers are keen to bring Jackson back, but he is sure to hit the open market on March 13 when free agency begins. The 29-year-old should get the most lucrative contract of any receiver on the market this year, but whoever invests in him will be getting their money's worth.

Peyton Manning

We all know what Peyton Manning has done during his storied career. He is a four-time MVP, an 11-time Pro Bowler and the holder of a number of NFL records, with more just over the horizon. Now that he is set to hit free agency, his health is the only question.

If he is as healthy as he seems to think he is, Manning would be an upgrade at quarterback for most of the NFL. He will immediately own the respect of whatever locker room he steps in to, and he will also force those around him to work twice as hard just to keep up with the soon-to-be 36-year-old.

There are a bunch of teams around the NFL that could use an upgrade at quarterback, and Manning will certainly provide that wherever he goes. He might be pricey, but he should immediately make everyone around him better. 

He is the best quarterback available this offseason, and he is likely to be off the market quickly.

Mario Williams

If your team needs an instant upgrade to its pass rush, you should be praying Mario Williams comes to town. Williams will almost surely be the most sought-after defensive player in this free agent class, and don't be surprised if he signs a monster deal quickly.

The No. 1 pick in the 2006 NFL Draft has played all six of his NFL seasons with the Houston Texans, but he missed most of the season with a torn pectoral muscle. The team has apparently decided to move on from Williams. 

In 82 career games, the N.C. State product has 53 sacks and 11 forced fumbles, which are elite numbers. Williams is just 27 years old and is a two-time Pro Bowler and a two-time All-Pro pick.

The best part about what the big guy brings is that he is scheme-versatile—he can play defensive end in a 4-3 or outside linebacker in a 3-4. 

He is sure to be a big upgrade to any team's pass rush.

Carl Nicks

Carl Nicks is one of the best guards in the NFL, if not the best. At 6'5" and 343 pounds, the Nebraska product has great size, quickness and outstanding feet. He is also a mauler in the run game who has a serious mean streak. 

Nicks is just 26 years old, which means he's entering his prime, so whoever lands him will almost certainly be acquiring a guy who could start for the next decade on the inside of the line.

He is a two-time Pro Bowler and a two-time All-Pro who has also been a part of an offensive line that paved the way for a Super Bowl title in 2010. 

Nicks won't come cheap, but he is the kind of interior lineman who makes everyone around him better by taking pressure off of them.