MLB

JOBA ‘BON AGAIN

BOSTON – Jonathan Papelbon is the Red Sox closer. That should be the answer the next time it is suggested Joba Chamberlain will soon be heading from late-game relief to the Yankee rotation.

For Brian Cashman is no more determined to see Chamberlain ultimately join Phil Hughes and Ian Kennedy in the rotation for the long term then his Red Sox counterpart, Theo Epstein, was to unite Papelbon, Josh Beckett and Daisuke Matsuzaka. Papelbon had 35 saves and a 0.92 ERA in 2006. Yet after that season the Red Sox resolved he would return to his role in the minors: starting pitcher. The front office salivated about building a rotation around three high-end 26-year-olds (Beckett, Matsuzaka and Papelbon). This was the grand plan.

But plans eventually must rub against reality. And this was reality: Papelbon was great at the end game, his potential replacements (Joel Pineiro or Mike Timlin) paled dramatically by comparison, and Papelbon wanted to stick in the pen. The plans evaporated. Papelbon stayed the closer, the Red Sox won another title, in part, because of Papelbon’s dynamic end-game touch.

“Over time I just decided that it was what I wanted to do,” Papelbon said. “It was what made my heart content. If your heart is happy, you have a better chance to be successful. So I think this is really about what is in [Chamberlain’s] heart.”

For now Chamberlain is playing good-teammate poker, betraying nothing as he says he will do whatever is best for the team. Papelbon, though, declared that at some point it must be Chamberlain who states what makes him happiest, what makes his adrenaline percolate most.

“This is not a decision that can be made by just a manager or a general manager,” Papelbon said. “The final decision really rests with him. You have to sit and talk with him and find out what he wants most.”

Chamberlain said, “I try not to think about [having to make a decision]. But you know it is going to come up.”

For now, Cashman seems immovable, claiming the value of a top-of-the-rotation starter is far greater than even an end-game force. Except, again, plans rub against reality. We are seeing in real time what the combination of Chamberlain and Mariano Rivera means for the Yankees’ success and confidence. You see them almost playing the game backward, feeling if they could lead after six innings they will win.

Chamberlain warmed up in the eighth last night and Rivera in the ninth. But in a performance of brilliant economy, Chien-Ming Wang kept the bullpen door closed. Wang two-hit the Red Sox on just 93 pitches in a 4-1 Yankee triumph – the Yanks’ first complete game at Fenway Park since Mike Mussina on Aug. 28, 2002. The Yanks are 3-0 when Wang starts, but also 4-0 in games in which both Rivera and Chamberlain appear.

That is hard to ignore. The plan was once for Rivera to return to the rotation. But he kept bringing steady genius to the late innings and made himself impossible to move. There would have been a revolt by teammates if it were even tried. The same now with Papelbon, who has a 1.37 ERA and a .162 batting average against since the beginning of 2006.

It is just guesswork what Rivera or Papelbon would have been as full-time starters. Now it is the same with Chamberlain. The sure thing is his superiority with the ball in his hands late. His teammates see that and it is going to be hard to sell them that the best maneuver is to transition Chamberlain to the rotation and hope that a Brian Bruney or Ross Ohlendorf can do a fair imitation of Joba the reliever.

“He’s had success out of the bullpen,” Papelbon said. “Do you want to mess with that?”

Joe Girardi said, “I don’t think about that [long-term decision] because this is where we need him now. I have enough to worry about without dealing with stuff that is down the road.”

The decision just might make itself. The Yankee personality is beginning to coalesce around the Jo-Mo duo, and Chamberlain more and more is indicating a temperament more all-out a few times a week than once-a-week starter. That was what drove the Papelbon decision to a large extent. Papelbon’s makeup was more conducive to the environment late in the game.

“It is a tough decision,” Papelbon said. “It is not easy. It is not something you decide in a day or two. It took me all of spring training [in 2007]. But over time my heart told me what the right thing to do was.”

joel.sherman@nypost.com