The Cowboys have been very active this offseason.

They've made more moves this year than they have in six offseasons, and have done a good job of addressing areas of the team that weren't very good in 2011.

However, with all the free agent signings, Dallas had to let a few players go. Several players who have been important to the Cowboys success over the past few years will be playing for different teams in 2012.

Here are five key players that the Cowboys lost to free agency in the 2012 offseason.

Laurent Robinson

The Cowboys lost one of the biggest surprises for them in 2011. Robinson emerged as one of Tony Romo's most reliable targets a season ago.

Robinson hadn't done much in his previous four seasons in the NFL. In 14 games with the Cowboys, he almost equaled his production for his entire career. The wide out caught 54 balls for 858 yards. He was integral in the Cowboys success in the red zone. He led the team with 11 touchdowns.

Dallas has two capable receivers in Dez Bryant and Miles Austin, as well as a good tight end in Jason Witten. However, Bryant still hasn't reached the 1,000 yard mark since entering the league, and Austin suffered through injuries in 2011.

Robinson provided some nice depth for the Cowboys last season. They didn't expect him to get $32 million from the Jaguars, and Dallas hasn't replaced him with an equal talent through free agency.

Terence Newman

Dallas decided that Newman wasn't worth the $8 million he was set to make next season, so they decided to release him.

Newman was once one of the Cowboys most reliable defenders. He was selected to the Pro Bowl in 2007 and 2009.

But the former first round pick is no longer the player he used to be.

He managed to intercept four passes last year, but had a poor overall season. He was bad down the stretch when teams began to pick on him, and was a major reason why Dallas missed the playoffs yet again.

The Cowboys drafted a cornerback with the number six overall pick in the draft and signed Brandon Carr to a lengthy deal. The Cowboys are much better off with Newman's contract off the payroll, and his poor play far away from Dallas.

Bradie James

The Cowboys lost another staple of their defense in Bradie James.

Dallas will certainly miss the linebacker. He played 142 out of a possible 144 games for the Cowboys since 2003. He recorded at least 100 tackles every year from 2006-2010. He led the team in tackles for four straight seasons, and won't be easily replaced.

James didn't have nearly as much of an impact in 2011. He had just 44 tackles, and lost playing time to Sean Lee. The team brought in Dan Connor from the Panthers, who will likely take his playing time at the inside linebacker position.

Nevertheless, James was a captain on defense and his presence will certainly be missed in the Dallas locker room.

Martellus Bennett

The loss of Bennett might be described by some as addition by subtraction.

The tight end was a disappointment for much of his Cowboys career. He was selected in the second round of the 2008 Draft, even though Jason Witten was already on the roster. Dallas owner Jerry Jones said he would bring another dimension to the offense, but Bennett never lived up to the hype.

He didn't produce on the field, catching just 85 balls for 846 yards in four years.  Bennett also caused some distractions off the field. He caused controversy in 2010 when he questioned whether or not Tony Romo should be the starting quarterback.

Losing Bennett shouldn't have much impact on the Cowboys. They will never see the tight end live up to the potential he has often been praised for having.

He signed with the Giants in the offseason.

Mat McBriar

Losing their punter could actually be one of the moves that comes back to haunt the Cowboys the most in 2012.

Dallas can still sign McBriar if they want to. He is a free agent, but the Cowboys haven't made him an offer, and he is free to join any team he wishes.

McBriar missed the end of the 2011 Season, but was one of the best punters in the NFL before his injury. He was selected to the Pro Bowl in 2006 and 2010. He led the league in gross punting average and net average in 2010.

If some other team signs McBriar to a multi-year deal, the Cowboys could be kicking themselves when opponents have good field position for most of next season.