Although they have not yet made a trade or signing, the New York Mets have been very involved in the bullpen market so far this offseason. They want to add high-quality relievers to their bullpen so they can lighten the load on their starters, and also not let as many late leads slip away as last season.

Mickey Callaway, the team's new manager, said on Tuesday he is "not locked into" having a set closer next season. He may use a closer by committee in which he bullpen usage is determined by matchups and the game situation rather than the inning. Here's what Callaway told reporters:

"I think we're going to pitch guys when it makes sense, and we're going to pitch guys to our strengths, and they're going to face the batters they should be facing. If that means he's going to close every game, that could happen if it lines up that way. We're not locked into that. I think that we have to make sure we get to a save situation, and if we can't get there, it doesn't do any good to have this guy be named the closer. So we're going to pitch guys when it makes sense, and we're going to do everything we can to win every night."

Callaway spent the last few seasons as Terry Francona's manager with the Indians, so he saw how Francona used Andrew Miller and Cody Allen in the late innings. Allen was the primary closer -- he saved 30 games while Miller saved two -- though Miller was the "moment of truth" reliever, so to speak. Whenever Francona felt the game was truly on the line, Miller was on the mound, regardless of inning.

Mets closer Jeurys Familia could be used in different situations next season. USATSI

Next season Callaway hopes to use a similar system with the Mets, minus the set closer. Right now his top relievers are lefty Jerry Blevins and righties Jeurys Familia and A.J. Ramos. Depending who the team adds this winter, the plan could be to have those three share closing duties in a sense. Blevins faces the tough lefties whenever they're due up and Familia and Ramos get everyone else.

This sort of bullpen usage sounds great it in theory, but it can be difficult to put into practice. Baseball players are creatures of habit and relievers like to have an idea when they're going to pitch, so they can go through their routine. Guys like Miller, who are willing to able to pitch at any time, are hard to find. Perhaps it'll work for the Mets and Callaway. If he doesn't, they can go right back to having a set closer.