Knighton, who arrived at training camp more than 20 pounds overweight, was cleared to practice Saturday and could play in the team's second preseason game next week. He said he's "somewhere in the 340s," still leaving him some weight to lose before getting to the 335 pounds the team feels will get him in "fighting shape."
"I'm just happy to be back with the team," Knighton said. "Had to shed a few to get back out on the field. I did that. Now I'm just ready to get some football stuff done."
A third-round pick from Temple in 2009, Knighton has been on a strict diet and exercise routine the last two weeks. He passed his conditioning test before camp, but a high heart rate prompted team athletic trainers to be cautious about putting him on the field in sweltering heat and humidity.
"That scared them the most, just knowing we'll be in the heat," Knighton said. "They were happy I made the test, which showed I did do something in the offseason. They're just worried about me health-wise. They wanted me down to a weight that I would be able to make it through all of practice."
Team officials, including general manager Gene Smith, coach Jack Del Rio and line coach Joe Cullen, warned Knighton about the long-term health effects of being overweight. They also made it clear his NFL career could suffer if it continues.
"There's been plenty of talking to him," Del Rio said. "He's heard all the words he needs to hear. It's really up to him to make the changes that are necessary in his own life."
Knighton also arrived at last year's training camp "way out of shape, way overweight," he said. He insisted he worked out more often this time around and blamed the NFL lockout for his preseason issues.
"It's a learning process," he said. "It wasn't as bad as last year, but it's something I've got to work on being a big guy."
Del Rio said Knighton still has some work to do before he's locked into playing Friday against Atlanta.
"We'll see how he goes through the week," Del Rio said. "He's worked hard to get down to where he had to get to be able to be out here. We've been working him sometimes three, four times a day getting him right. He's actually in halfway decent shape.
"We'll begin to work on the other half now and part of that is getting acclimated to wearing the pads and keeping knees bent and playing with a good pad level and doing the things you have to do to be good inside for us."