MINNEAPOLIS -- The Home Run Derby will have a new champion this year.

Minnesota first baseman Justin Morneau, winner of last year's Derby, has declined an invitation to defend his title this year, meaning a new home run king will be crowned Monday in St. Louis.

"They asked me yesterday," Morneau said before the Twins' series opener against the Yankees on Tuesday. "I said I wasn't going to do it."

The National League roster for the Derby has already been set, with four first basemen scheduled to take part. The Brewers' Prince Fielder, the Phillies' Ryan Howard, the Padres' Adrian Gonzalez and Albert Pujols of the host Cardinals will swing for the fences of Busch Stadium for the NL.

With the American League contingent still up in the air, what would Morneau think of his teammate and fellow All-Star, catcher Joe Mauer, taking part in the Derby?

"That'd be great if he did," said Morneau, whose 21 home runs leads all Twins hitters. "I'd love to sit there and watch him just as a fan. I'd have the best seat in the house, sitting on the field and just enjoy watching my teammate, instead of sitting there having to be focused and not really get to enjoy the thing."

Mauer admitted he'd have a tough time turning down an invitation to at least try and keep the Home Run Derby trophy in Minnesota.

"If they ask me, I don't think I could say no," said Mauer, second behind Morneau on the team with 14 homers. "I know watching him the last couple of years, it's a lot of pressure. Still, it looked like it was a fun deal."

Despite not exactly filling the prototypical role of a home run hitter -- Mauer, who never totaled more than 13 home runs before this season, is more likely to hit .400 than blast 40 homers -- his coaches and teammates wouldn't be surprised if Mauer did well in the contest.

"Joe, in the home run hitting contest? He'd probably win it," Twins manager Ron Gardenhire said. "You know it and I know it. Just to let people know he can hit home runs. Nothing would surprise me that Joe does."