Green Bay Jeremy Thompson knows that most people consider him the underdog.

Thompson realizes he doesn't have the name recognition of his challenger. He doesn't carry the label of first-round draft pick. And at the end of the day, he might not be the people's choice either.

But Thompson is doing all he can to upset Clay Matthews and win a starting outside linebacker job for the Green Bay Packers.

"I know more people out there probably know about Clay than they do about me," Thompson said. "But I'm excited to show the fans I can play, and I'm even more excited to show my teammates the same thing. I want to show myself that I can play in the NFL, and I think it can work out."

The Packers sent a second-round draft pick and a pair of third rounders to New England for the 26th overall pick in April's draft and then selected Matthews. When a team gives up that much for a player, it usually throws him into the starting lineup from Day One.

But Thompson has done all he can to make the Packers' choice a difficult one. A little more than a week into training camp, the two had split the repetitions with the No. 1 defense and neither player had surged ahead.

Smart money is probably still on Matthews to emerge if he can remain healthy. But Thompson has made a smooth transition from defensive end, and it would be foolish to count him out.

The fact Thompson is even in the running qualifies as a major surprise. A fourth-round draft choice out of Wake Forest in 2008, Thompson had a non-descript rookie season. He played in nine games at defensive end, starting three, and finished with 13 tackles, no sacks, no interceptions, no fumble recoveries and no forced fumbles.

"Not good at all," Thompson said when describing his rookie season. "Of all the plays I got, I just didn't take advantage. I think I did some good things and showed some flashes, but it just wasn't up to my par."

But the Packers' switch to a 3-4 defense might prove to be a boost to Thompson's career.

Thompson played at 265 pounds last year and was an undersized end in a 4-3 base. Now, the 6-feet-4-inch Thompson is down to 255 pounds, has taken his body fat from 12% to 8.5% and has the ideal body type to play outside linebacker in this scheme.

"He's extremely athletic," Packer coach Mike McCarthy said earlier this offseason. "He's a natural pass rusher. His experience playing defensive end really will help him this year as it carries over to the outside linebacker position."

Thompson got an early leg up when Matthews was sidelined by a hamstring injury during workouts in June. But it's been back and forth between the two throughout training camp.

Thompson opened with the No. 1 defense for the first few practices, but Matthews stepped in when Thompson was sidelined with cramps in the third practice. Both players proceeded to get their share of work with the No. 1 defense until late last week when injuries struck.

Matthews re-aggravated his hamstring injury and was ruled out of last Saturday's intrasquad scrimmage, an event that was later cancelled due to inclement weather. Thompson missed time late last week with a groin injury but was cleared to play in the scrimmage and would have started.

"I just think it's going to be a great competition," Thompson said of his battle with Matthews. "I just have to make plays and eliminate mental errors. Just play good, smart football."

There have been times when left tackle Chad Clifton has downright owned Thompson. There have been others when Thompson's athleticism has sparkled, like the day last week when he jumped into the air to nearly intercept a Brian Brohm screen pass.

"I'm kind of a shy guy at first, and it takes a while for people to get to know me," Thompson said. "And last year was tough because the speed of the game is so much different, and that took me some time to adjust.

"But this year, I just think I came in so much more focused. I knew where I fit in the locker room and had my niche there. I've learned the defense as fast as I could and just tried to be aggressive. Right now, I just want to be physical, do my job and make plays."