"I'm just trying to compete against myself, to get back into starter shape," he said.
That particular competition started two weeks after the 2006 season ended. Knowing that he'd likely be given an opportunity to return to the rotation in the wake of Barry Zito's departure, Kennedy, who was a starter during his stints with the Devil Rays and Rockies, got right to work when the calendar turned to November.
"Workout-wise, I didn't change much, but I definitely started earlier than I normally do," he said. "When you're in the bullpen, as the year winds down, you cut back on your running and lifting because you're a little worn down, and you want to make it to the end. So you actually get a little bit out of shape, if that makes any sense."
Kennedy, listed in the A's media guide at 252 pounds, was tipping the scales at 268 at the end of last season. Some of the extra weight, he said, was the result of being on the disabled list for three months with shoulder tendinitis.
That his wife, Jami, was pregnant didn't help, either.
"Jami wanted to eat everything when she was pregnant," Kennedy explained. "And they say the husband always gains sympathy weight or whatever. Well, I did."
The Kennedys welcomed son Steffen Kaige into the world on Nov. 17, and with Jami's eating habits back to normal and Joe paying more attention to his own diet in the offseason, the husband dropped 20 pounds.
"You can definitely tell he's slimmed down," said catcher Jason Kendall, who caught Kennedy's bullpen session Sunday. "He looks great. Threw real well, too."
Kennedy, who was hard at work in the weight room shortly after his throwing session, admitted that he's gained back eight of the 20 pounds he'd lost since arriving in Arizona on Feb. 6.
"I kind of took a week off from the diet, just to enjoy my last week of freedom before camp," he said. "Plus, they have In-N-Out Burgers down here. That might have had something to do with it."
Now at 256 pounds, Kennedy would like to get under 250 as soon as possible.
"If you want to lose weight down here, it's not hard," he said. "I'll have no problem losing 10 pounds this spring."
Being lighter, Kennedy figures, will go a long way toward helping him reach his goals.
"I'm not a big goals guy, really, but I'd like to stay healthy and pitch at least 180 innings," he said. "The ideal is 200 [innings] and 32 [starts]; if you get there, you're healthy all year."
After returning from the DL -- he missed 84 games -- last August, Kennedy put the finishing touches on a tremendous, albeit truncated, season. He didn't give up a run in his first 11 outings back, and he ended up with a team-best 2.31 ERA in 39 appearances in the first season of his big-league career without a start.
"He was absolutely filthy out of the 'pen last year," Kendall said. "And that was with three pitches. He's actually got five, from when he was a starter before, so now he just brings the other back into it.
"I faced him when we were both in the National League, and he was good then. But he's better now. I think he's going to have a great year."
As for the shoulder and arm trouble that plagued him last season, Kennedy said it's long been a non-issue in his mind.
"I knew that as soon I came back from the DL," he said. "It was 100 percent then, and I did a lot of upper-body work over the winter, so it's even stronger now. I'm stronger than I've ever been."