That's because Jenkins' knee is just fine.
Just 10 months after tearing his anterior cruciate ligament (ACL) in his left leg, the veteran nose tackle is back on the football field and has been mixing it up with his New York Jets teammates for the past two weeks.
"This is here, OK?" Jenkins said as he grabbed a hold of his left knee. "It's back."
Jenkins, considered to be one of the NFL's premier interior defensive linemen, tore the ACL in his right leg during the 2005 season. He said he expects to have full strength in the left knee by the start of the regular season based on his successful recovery five years ago.
"He's really working on his technique," said Jets head coach Rex Ryan. "When you get up there in your career, you should be a better technical player. You need to be to get by, to play like a dominant guy."
Now in his 10th year in the league, Jenkins says he is practicing and playing smarter by putting more emphasis on mechanics rather than pushing himself and simply using brute force. That, however, does not mean he is trying to ease up on his recovered knee. Instead, Jenkins said that "being intelligent about what I do" is going to allow him to play the game at the high level he's been accustomed to.
"I'm out there banging, I'm out there doing my job, I'm out there handling my business," Jenkins said. "Being smart about (my knee) is totally different than nursing it. Nursing it is going and sitting at the bike with (the trainer). I'm not nursing. I'm practicing, I'm playing, I'm tacking, people are falling on my leg, things are happening -- that's called football. I'm fine."
After losing more than 30 pounds before the start of training camp, the 360-pound tackle said he feels stronger than he did "a while ago."
"When you change diet habits and you do lifestyle changes, it's just overall going to improve your character," Jenkins said. "That's something that I feel good about. Balancing my body out is the focus now, getting used to those movements that I haven't performed in a while and getting out here and getting better with the guys."
Ryan said he thinks Jenkins is in "great shape" and is ready to play a game at any time, adding that Jenkins' injury last year made confidence a hurdle he was forced to confront this summer.
"He had to get over it himself," Ryan said. "The hitting, the collisions, the going on the ground and all that stuff. He's passed that with flying colors, so I know he feels good about that."
Nick St. Denis covers the Jets for GreenAndWhiteReport.com