Make no mistake, the Yankees were counting on Joba Chamberlain being an important part of their bullpen this season.

He wasn't going to be ready for the first few weeks of the regular season, after undergoing Tommy John surgery last June. But he was definitely in their plans.

"We thought it was realistic to get him back around June, and I don't think that's so realistic now," manager Joe Girardi said on Friday. "It's a power arm that was gonna come back strong. We were thrilled to death the way he was throwing the ball."

Now the Yankees have to prepare as if they will be without Chamberlain for the entire season. The question is, who will step up in his place?

Girardi is very fortunate to still have the trio of Mariano Rivera, David Robertson and Rafael Soriano at the back end of his 'pen. But he'll need more than that to get this team to October.

And, just think about the worst-case scenario? Soriano spent more than two months on the disabled list last season. Robertson is still coming back from suffering a bone bruise in his foot this spring, in another freak accident, at home. And Rivera, as wonderful as he is, is also 42 years old, don't forget.

My colleague Andrew Marchand brought up David Aardsma yesterday, and he will be an intriguing option, when he's ready.

The 30-year-old righty had Tommy John surgery in July, a month after Chamberlain. The Yankees just signed him late last month, and Cashman said at the time that he made the move with 2013 more in mind. But Aardsma, who collected 69 saves in 2009 and 2010 combined with the Seattle Mariners, becomes much more valuable this season now.

Other veterans may get increased roles -- like Cory Wade, who had an excellent season last year, posting a 2.04 ERA in 40 appearances.

Or maybe the Yankees will call upon one of their top prospects from the minors, like Manny Banuelos or Dellin Betances, converting them into relievers, at least for the start of their major league careers?

That's what they did with Chamberlain, once upon a time, back in 2007. My, how long ago that seems now.

UP NOW: The full story on Chamberlain's injury, posted yesterday after Cashman first revealed the news to reporters.

ON DECK: After spending an hour in the Yankees clubhouse later this morning, I'll be making the trip to Joker Marchant Stadium in Lakeland to see the Yanks play the Detroit Tigers. Freddy Garcia will get the start, his first since suffering a bruised hand on March 14.

QUESTION OF THE DAY: If the Yankees are without Chamberlain for the entire season, how big a loss is it?