GREEN BAY, Wis. (AP) Randall Cobb can't prove it, but he believes wearing a microphone during the Packers' playoff game at Arizona led to the punctured lung that knocked him out of the season-ending defeat.

''I'll never be mic'd up again,'' Cobb said following Thursday's workouts.

During the first quarter of the game against the Cardinals, Cobb made a leaping catch and landed on his back. A penalty eliminated the 49-yard gain and Cobb was taken to a hospital, where he stayed overnight.

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''I've never had a problem with it before,'' Cobb said. ''Possibly, it was just the way I landed. I landed flush on my back with the battery pack on. You probably won't land too often like that but unfortunately the one time I did, I had a bad injury from it.''

Cobb is back and practicing after an eventful offseason. He became engaged and graduated from Kentucky, where he spent three seasons before entering the draft and being selected by the Packers in the second round in 2010. Quarterback Aaron Rodgers attended the ceremony.

Cobb said he was 32 credits short of getting his degree in community leadership and development in the college of agriculture, food and environment when he left for the NFL.

''I've been working on it for five years,'' Cobb said. ''I just got so close these last couple years that I just wanted to finish it as soon as I could. I thought the older I get, the more I wouldn't want to go back. It's something that I'm glad that I did and something that, moving forward, I'm hoping I can get my MBA in the next five or seven years.''

Cobb's not sure what he ultimately intends to do with his degree, but football is his focus for now after a subpar season. After piling up 91 catches for 1,287 yards and 12 touchdowns in 2014, Cobb caught 79 passes for 829 yards in 2015. Three of his six touchdowns came in a Week 3 victory over Kansas City, and his 10.5-yard average was the worst of his career.

Cobb sustained a shoulder injury in the preseason, which limited him early. Plus, Jordy Nelson's season-long absence allowed defenses to smother Cobb. Green Bay scored a touchdown less per game.

''I'm really excited about this year,'' Cobb said. ''Yeah, there was a lot of things going on last year but none of that stuff matters. I didn't perform at the capacity that I know I can perform at. At the end of the day, nobody cares about what you had going on. Did you play well or did you not? I'm the only one who can change that.''

NOTES: After playing mostly inside linebacker for the past season-and-a-half, Clay Matthews is back at outside linebacker, where he feels at home. ''I feel like that's my most natural position but it almost feels like I never left that room and never left that spot of rushing off the edge. It feels good to get back out there and work with Pep (Julius Peppers) and the other boys. I'm excited about it. It's obviously a position that I'm most comfortable with.'' . Nelson (recovering from torn ACL) will not participate in 11-on-11 drills until training camp but did catch passes from Rodgers and ran a few routes during individual drills. ''It's very important for Jordy Nelson to catch the football from Aaron Rodgers,'' coach Mike McCarthy said. ''I think that's something that can't get lost in his coming back. Jordy's human. Aaron throws the football differently than the other quarterbacks that we have here.''