Tim Duncan 'stressing' about weight gain

Tim Duncan may be having trouble adjusting to life after the NBA.

A month after announcing his retirement, the San Antonio Spurs legend is still trying to get used to no longer having to train and eat in such a way that keeps him in game shape, according to his former teammate Bruce Bowen.

"Last week, (Duncan) picked me up from the airport and we're talking, and he's stressing that he needs to start working out," the 13-year NBA vet told DeAntae Prince of SI.com.

"Those (pounds) start adding up, and the athlete in him says I can't be this big or I can't be this heavy, and I don't see him as heavy. You look at his frame and it's not there, but when you're accustomed to doing things a certain way you can feel yourself expanding."

Bowen, who hung up his sneakers in 2009, says that feeling never fully goes away, based on his experience.

"It's one of those things that kicks in even now," the 45-year-old admitted. "You feel your waist expanding or your belly getting out there, and you're like, 'Oh, I got to do some sit-ups, I got to go run, I need to something,' because we've worked out for so many years. And while you don't want to do it to that degree, at the same time you want to make sure you keep your body right."

At this rate, post-retirement Duncan could become "The Bigger Fundamental."