What hasn't been determined, Girardi said Saturday morning, is precisely how Chamberlain will be used.
Chamberlain earned the save in yesterday's 2-1 victory over the Tigers, pitching the ninth and allowing two hits but no runs, getting a double-play grounder and a strikeout.
The 24-year-old, of course, knows the closer role on the Yankees' 2010 team already is taken.
"There's someone in front of me I think you guys may have heard of,'' he said with a laugh. "I'm going with the [assumption] I'm probably going to lose that one.''
The question: Will Chamberlain, who threw only fastballs and sliders yesterday, reprise the role that made him an instant star in 2007 as Rivera's setup man?
Before the game, Girardi answered with a definite maybe.
"I have a faith in the guys that are down there and guys that have had a lot of success down there, but it's not in a sense ironed out like it was from July 4 [last year] who's going to be our eighth-inning guy,'' Girardi said, referring to Hughes taking that role from Brian Bruney last season.
"That's something we have to look at over the next week and maybe the first couple weeks of the season and see how it plays out. We had some different people in and out of that eighth-inning role last year and then Hughsie kind of locked it down. You'd like to see someone lock it down.''
Chamberlain seems the natural fit because he's done the job before. He looked plenty comfortable against the Tigers.
"As far as routine, it was great, it felt pretty good,'' he said. "Good first time, a 2-1 ballgame. You don't want to give up the lead, that's for sure, and lose the game, so it was a good position to be in for my first one.''
Girardi liked what he saw from Chamberlain, who topped out at 94 mph and got Scott Sizemore swinging at an 85-mph slider to end the game.
"I thought he attacked, he was ahead,'' Girardi said. "For his first time out of the bullpen after starting, for him I thought it was positive, and we'll get him back out there again.''
When asked before the game if Chamberlain's roster spot is assured coming out of camp, Girardi raised some eyebrows by saying "there are no guarantees.'' Knowing how that might be interpreted, he amended the comment. "I expect him to be in our bullpen and pitching important innings for us,'' he said.
Girardi said with Chamberlain plenty stretched out, using the righty as a two-inning setup man - a la Rivera in 1996 - will be considered. But he said he is likely to use him "more in a traditional sense'' because of the depth in the bullpen.
David Robertson is a possibility as Rivera's setup man, but the role likely is Chamberlain's to lose.
Chamberlain said he welcomes the adrenaline rush that accompanies coming out of the bullpen. "When the door opens, you get it going,'' he said. "That feeling you get running out there.''
And if he looked comfortable against the Tigers, Chamberlain said it's because he was - with the routine, the mind-set of pitching one inning and the knowledge that he can, in general manager Brian Cashman's words, "just let it fly.''
"There's always a sense of knowing what you're doing when you get a definite answer to what's going on,'' Chamberlain said. "Just one of those things where you have to embrace it and be honored to be in that position and try and get better every day.''