MINNEAPOLIS -- Boof Bonser headed home this offseason with one thought on his mind: lose weight or lose his job.

Judging by the much trimmer physique that Bonser debuted at TwinsFest this weekend, it's clear that he wasn't about to hand over his rotation spot that easily.

Bonser has lost about 20 pounds since the end of the season, a result he credits to working with a nutritionist and stepping up his workouts.

"I took it as if I didn't do it, my job was on the line," Bonser said. "I think by losing the weight, I'm showing them that I want to stick around here and pitch in Minnesota. I know I still have to do it out on the field, but it started with step one, losing the weight they wanted me to lose."

Bonser's dramatic weight loss came after the Twins sat him down toward the end of the 2007 season and told the right-hander that they felt he needed to make some changes.

The 26-year-old had been struggling to make it past the fifth or sixth inning in his starts, and the club felt the weight had something to do with his lack of stamina. So the challenge was issued to lose somewhere between 10 to 15 pounds.

Holding two water bottles and an apple as he waited for an autograph signing on Saturday, Bonser talked about what it has taken to reach this point. He said that changing his diet to include more healthful foods, combined with more intense cardio and agility exercises, helped the weight come off pretty easily.

It's been a successful plan. Still, he admits that it wasn't something he accepted with open arms at first.

"It's always tough to hear that you need to lose weight. I've never been a small kid," he said. "But between that meeting and getting sent to the bullpen for 'x' amount of days, it all hit me. I came up as a starter and always have been a starter. I didn't know what bullpen life was like. And I guess you could say that I didn't want any part of it."

The reaction to Bonser's new appearance at this weekend's event was immediate. Everyone from teammates to the front-office staff to the fans have commented on how good he now looks.

And with Bonser's clothes now seeming to hang off him, his teammates also took the chance to chide him a bit.

"Some of the guys are telling me I need to get my clothes tailored," he said with a laugh.

But the weight loss is something that Bonser considers to be just the first step. He knows that it will take much more for him to prove to the Twins' coaching staff and front office that he deserves a spot in the rotation.

"There are bigger goals that I have for myself," he said. "Obviously, the weight was one of them, and I accomplished that. But I definitely see other goals ahead. I want to be better than I was last year."

Waiting game: The contracts that the Twins handed out to first baseman Justin Morneau and outfielder Michael Cuddyer this week were a sign that the club is making a conscious effort to lock up its core players.

But one player is still waiting to see if he's considered to be in that "core" group.

Closer Joe Nathan is entering the final year of his contract, and he said on Saturday that so far no extension talks have taken place between him and the team.

Nathan expressed some slight optimism that might change after seeing those deals completed. Still, with the rumors this offseason that the team might be willing to trade him, he doesn't quite have a handle on what Twins are thinking in his case.

"I don't know if they are interested in doing something long-term, and I don't know if they feel like they would be able to," Nathan said. "We haven't had any conversations for quite a while now. I think they are going to have to spark up the conversation and give us a feeling of what their thoughts are, what they can afford and what kind of money is available."

Despite the two signings this week, Nathan expects that his status won't be addressed until the club settles the Johan Santana situation.

"Getting those two guys signed, it moves me up on the ladder," he said. "Now we have to find out what they are going to do with Johan. Hopefully, after that I'm at the top of the list, and we can figure out what we're going to do."

Outfield, please: Heading into the 2008 season, the expectation is that the Twins will use Craig Monroe primarily in the designated hitter spot.

But Monroe has some other plans.

"That's what they've talked about, but for me it's just talk," Monroe said. "I think when we get to Spring Training and they get a chance to see what I can do on the defensive side and that I can hit pretty well, they'll see that I'm a good outfielder. And I'll give myself a chance to play [there]."