MLB

YANKS GOTTA FIND FOUNTAIN OF YOUTH

IF it’s about time the Yankees rotation got young, time also will be needed for Phil Hughes and Ian Kennedy to be everything the team wants them to be. After three straight first-round knockouts, everybody is ready for a youth movement. But it will get old fast if growing pains break the chain of 13 postseason appearances.

The streak began in 1995 partly due to the impressive break-in of Andy Pettitte, but has been maintained mostly because the Yankees threw big bucks at established pitchers. Though not all of them worked out, the most lasting return they have ever received from one arm is from Mike Mussina’s, which won an average of 15 games during the six years of the $88.5 million contract he signed before the 2001 season.

Predictably, that deal worked out a lot better, so far, than has the two-year re-up. Following an 11-10, 5.15 ERA in 2007, last night Mussina debuted for 2008 with four runs in 52/3innings of a 5-2 loss to the Blue Jays.

Helping to make his own bad first-inning luck on a late break to first on a ball Jason Giambi bobbled, imprecise on a flat and down-the-middle slider Vernon Wells crashed for a two-run homer, unable to finish off Aaron Hill, whose RBI single chased Mussina in the sixth, there was little encouraging in the results, leaving the pitcher to find solace in his form.

“I have to make fewer mistakes,” he said. “A couple guys I had 0-2 ended up on base.

“But when [David] Eckstein was fighting off stuff, I still had stuff to go to and he hit into a double play. There are days they foul them off that you feel there’s nothing left to do.

“Hopefully I’ll [pick up] a mile or two an hour as we go, but I got the ball where I wanted most of the time, got to [91] pitches and felt good at the end. If I can have this 30 times I can live with this.”

The Yankees will have to, unless they want to close one of the best eighth-inning shows in baseball by adding a third babe, Joba Chamberlain, to the rotation, or move good prospects before July 31. Mussina’s $11 million has to be better spent this season than last and not just on the every fifth day – boy, they can only pray – a 39-year-old gets the ball.

“He’s real important,” said Joe Girardi. “Mike a lot of times has the ability to show how you get hitters out and the ability to relay it to teammates. Not all guys can necessarily do that.”

No disrespect expected from Hughes, Kennedy and Chamberlain, there has to be some do-as-I-do mixed in with the do-as-I-say for Mussina’s messages to resonate. He must be pitching to an ERA in the mid fours or Chamberlain is in the rotation and Kyle Farnsworth again a primary eighth-inning option, gulp.

“Mike has that look that he’s out to prove something,” said Girardi.

Mussina is joined in that regard by gray panthers Giambi, who is already bludgeoning belief that he can be an everyday first baseman, and Johnny Damon with Hideki Matsui, Bobby Abreu, and 36-year-old Jorge Posada, coming off a near-miraculous 2007, on the watch list.

Hughes goes tonight, a good thing, but the Yankees have the look of a team dangerously too old and young at the same time.

Of course, their deep lineup allows more room for breakdowns than would their pitching should Pettitte, pushed back already on the first turn of the rotation, be unable to make 28-30 starts and the worst fears for Mussina be realized.

“His mechanics are good and he uses his lower half [body] well, why, I think, you haven’t seen arm injuries,” said Girardi. “He works very hard, one of the reason he’s had his longevity.”

It’s been a major factor in the Yankees’ longevity, too, now correspondingly endangered.

jay.greenberg@nypost.com