Considering the solid season Calero had in 2009, it's the type of low-risk, high-reward signing the Mets needed for a relief corps that's already hurting.
"He had a very good year last year, and to be able to bring a guy like that on a Minor League deal to potentially compete in our bullpen, I think it's a good sign," Mets general manager Omar Minaya said.
"That's going to be up to Jerry as far as how they decide [where Calero is deployed], but he's definitely going to be a guy that is going to be in the mix for the bullpen."
Calero had what he called his best season while pitching for the Marlins in 2009, when he compiled a 1.95 ERA in 67 relief appearances, striking out 69 batters and walking 30 in 60 innings. He led Florida relievers in ERA and was fourth on the club in appearances.
Despite that, the 35-year-old couldn't land a Major League contract this offseason amid concerns about his shoulder.
Calero has had shoulder issues for a big portion of his career. More recently, he tore his right rotator cuff in 2007, missed more than 50 games because of the injury in '08, then was out of action for 18 games last year because of inflammation in the shoulder.
For the record, Calero said his shoulder now feels "great." And he agreed that this was a frustrating offseason.
"Yeah, it was frustrating, because last year was my best year, but I had to wait until two weeks after Spring Training started [to sign]," Calero said.
"I was just waiting for the call. [The Mets] called me, and I'm ready to start doing the job."
Calero said eight teams were interested in him, but it was all for Minor League deals so he could prove he's healthy first. According to the New York Post, his deal with the Mets is worth $850,000 if he makes the active roster, with an additional $650,000 available in performance bonuses.
The native of Puerto Rico has pitched for three teams in his seven years in the big leagues -- four with the Athletics, two with the Cardinals and one with the Marlins. He has a 14-12 record with a 3.24 ERA in 313 games (one start).
Kelvim Escobar, signed this offseason in hopes that he'd be the Mets' eighth-inning man, is dealing with right shoulder soreness and is not expected to be ready by Opening Day. Perhaps Calero could fill that void.
Regardless, a plethora of options for the bullpen is never a bad thing, Manuel believes.
"I don't think you can have enough arms," the Mets' skipper said. "Over the years, history tells you that depth is very important to the success of the team in the long haul of 162 games. I don't think you can ever have enough good arms. Hopefully, he can be a part of some of the decisions that we need to make."
Alden Gonzalez is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.