Terrance Knighton realizes vanquishing the story line that has followed him for the past three seasons is in his own hands.

That's why he intends for this to be the year when everybody stops talking about his weight because they don't have to anymore.

"It's not going to change overnight because I came in in good shape today," Knighton said on Wednesday. "I want to prove to them this year that I won't be a problem and go above and beyond their expectations and show that I'm committed to it and it's an area where I've matured and changed."

Knighton reported for the Jaguars' voluntary offseason strength program Wednesday, the first step in an offseason entering the final year of Knighton's rookie contract. The man affectionately known as "Pot Roast" to teammates and fans is fitter than he was when he reported to training camp last season after the lockout, and he intends to stay on that course throughout this offseason.

"I'm in the best shape I've been in since reporting as a rookie," Knighton said. "The number is a lot … lower than checking in last year when I came back during camp the high [360s], maybe even low [370s]. I'm 20 pounds less than that. They're happy where I am."

One of Knighton's strengths coming into the league was that he was as quick as he was while being as big as he was.

But while some players at his position could play heavier - Knighton mentioned the Patriots' Vince Wilfork, for example - Knighton's body type didn't lend itself to remaining effective as he added pounds. He watched himself on film and he realized how the extra pounds slowed him down.

"A lot of guys, you see it around the league with the big stomachs, it really doesn't affect them," Knighton said. "Mine's in the lower body, so that slows down my foot quickness and that's one of my areas that I'm really good at. … If I'm playing slow, there's no reason for me to be out there."

That's something Knighton has struggled with since his second season in the NFL. He came into the 2010 training camp overweight and was placed on a strict diet and cardio regimen to bring down his weight.

Knighton gained weight during last year's lockout, too, when he was away from the facility from March through July. After a surprise conditioning test to start the 2011 training camp, the Jaguars determined Knighton's heart rate was reaching dangerous levels. So he worked on his conditioning and didn't participate in team drills at the start of camp.

"When he's in great shape, he's as good a defensive tackle as there is," Jaguars defensive line coach Joe Cullen said. "I think he has exceptional qualities, super quick feet, he plays well. … When he hits the 330 range, when he's in an optimum weight, he's really quick on his feet and stays on his feet and can do all the things we look for in a defensive lineman."

Cullen saw Knighton briefly Wednesday and noticed he appeared to be in better shape.

For Knighton, it took consistency with his offseason regimen and it took determination not to take too much time off. It was the only way to change the narrative.

When Knighton met with Jaguars general manager Gene Smith at the end of the 2011 season, Smith plainly told him if he proved he could control his weight, he would be rewarded for that in his next contract.

"Going into my last year of my contract, that's obviously important to me," Knighton said. "If guys will tell you the money wasn't important, they're lying to you. But really I care about my health and longevity after football. I don't want to be remembered for the guy who had weight problems, I want to be remembered for the guy who turned it around."

He and Smith met again on Wednesday to talk about Knighton's goals. Knighton said it was a more positive conversation than they had three months before, with less concern and more anticipation.

Tania Ganguli: (904) 359-4401