NFL Free Agents 2012: Examining the Best Undrafted Rookies

Much like it was when the NFL's free agency period started, the post-draft world briefly intensifies due to all the rookie undrafted free agents that are available.

One prime example is Washington Huskies' running back Chris Polk, who according to the Sports Xchange and CBS Sports signed with the Philadelphia Eagles. This is a great move by Philly as LeSean McCoy needs a No. 2 complement in the tough NFC East.

In addition to Polk, other top undrafted rookies have recently been signed. Let's examine them and see how each fits their new team.

Tampa Bay Buccaneers: Leonard Johnson, CB (Iowa State)

According to Ryan Bass of the Bright House Sports Network, the Tampa Bay Buccaneers acquired Iowa State cornerback Leonard Johnson after the draft.

Johnson, who was a projected mid-rounder, is a gem for Tampa after the draft. A consistent performer for the Cyclones for four years, Johnson defended 32 passes, forced six fumbles, made 241 tackles and recorded six interceptions.

Tampa Bay only drafted one corner in West Virginia's Keith Tandy, so adding Johnson allows for the secondary to grow together. He's a technically sound defender that brings good size and physical play on the outside.

A reliable run defender, Johnson also has the potential to shut down top targets as he limited the production of Justin Blackmon in the Cyclones' win over Oklahoma State last season. With safety Mark Barron patrolling over the top, Johnson only enhances the potential of the young Bucs defense.

Oakland Raiders: Aaron Henry, Safety (Wisconsin)

Easily one of the most overlooked safeties in all of college football, Wisconsin's Aaron Henry joined the Oakland Raiders as an undrafted free agent, according to Steve Corkran of the Contra Costa Times.

Possessing solid size, speed and explosiveness, Henry produced well for the Badgers. With 181 tackles, seven picks and 24 defended passes during his tenure, Henry was Wisconsin's best defensive back.

The Raiders need a reliable safety to pair with Tyvon Branch as well, because Branch can roll down into the box and take on tight ends or receivers in the slot, as well as help with run support. Henry has the developed instincts to sit back in Cover 1 or 3 and help over the top of the corners.

Above all else, Henry's top speed will prevent many big plays downfield and with Branch filling for blitzing linebackers, Oakland's defense can screw up an opponent's game plan in the first quarter.

Considering that the AFC West has become a rather difficult division and the Raiders ranked No. 29 in total defense last season, Henry's addition will create more turnovers to slow down fast-paced offenses.

Philadelphia Eagles: Chris Polk, RB (Washington)

LeSean McCoy is arguably the NFL's best and most complete running back. Having gained over 1,600 total yards each of the past two seasons, McCoy has also accounted for 29 touchdowns during that span.

However, the Eagles offense does become vulnerable to getting shut down as McCoy hasn't had that complement back to change the pace. Well, Chris Polk (as sourced above, who signed) can provide just that as he brings the size, short-area quickness and power to Philly's offense between the tackles.

Between 2009 and 2011, Polk totaled 4,016 rushing yards, averaged over five yards per carry and scored 26 rushing touchdowns for the Huskies. The Eagles now have that powerful interior running that's a threat on short-yard situations and Polk is also a reliable pass-protector.

Polk's addition provides Philadelphia with the luxury of running a legitimate two-back set to get defenses off balance. Play-action up the middle and on bootlegs only becomes more dangerous, thus making Michael Vick a more prolific passer as his receivers see more single coverage situations down field.

Miami Dolphins: Jeff Fuller, WR (Texas A&M)

It was no surprise that the Miami Dolphins selected Texas A&M quarterback Ryan Tannehill at No. 8 overall.

Despite Tannehill being a risk, he will be reunited with his favorite college receiver in Jeff Fuller, according to Ben Volin of the Palm Beach Post. It's a great move since they need a receiver that brings impressive size, top speed and acceleration to the position.

In four seasons at Texas A&M, Fuller compiled almost 3,100 yards on 233 receptions and scored 34 touchdowns. Although he's not a physical receiver, Fuller can consistently beat single coverage, draw a safety over the top and out jump anyone in the red zone.

Reuniting with Tannehill and his former head coach Mike Sherman, Fuller's NFL development will happen quicker than most and Miami's offense will become much more balanced.

Provided that Reggie Bush continues his dual-threat presence in the backfield, the Dolphins' offense will be quite effective in 2012 off play-action and in the shotgun.

John Rozum on Twitter.