Joba Chamberlain is on the mound tonight for the Yankees against Roy Halladay, though we don’t know exactly for how long. Seeing as that he went for three innings last time out against the White Sox and threw 35 pitches, it’s safe to say that the Yankees would be OK with him throwing about four innings and 50 pitches.

The pitches really aren’t the main concern – it’s the innings, as the Yankees figure it all averages out over the long run. And yes, there’s a point to this post. It seems like every time we get around to Chamberlain in the rotation, there’s a segment of the fan base that becomes outraged (and then floods my e-mail box).

That’s OK, that’s what it’s there for. But I’ll reply in bulk and say once again, to recap, this is all about protecting the Yankees’ investment for the future in Chamberlain. He’s not a disposable type pitcher – if Chamberlain hurts his arm and goes the route of the Mets’ Big Three in 1996 (the example Chamberlain keeps bringing up), it’ll be a significant setback.

With his body type and injury history, it’s safe to say that there is a serious risk involved with Chamberlain. But this is Year 3 of the Joba Rules and slowly but surely, they are easing off the training wheels, and next year should be a pretty full season for him with 180 or so innings.

The thinking was that 160 innings of him as a MLB starter in 2009 would be more helpful than zero. And with a 7 1/2 game lead in the American League East, the Yankees have the luxury to play with such things. If Chamberlain goes four innings tonight and the Yankees lose, it’s not going to be the end of the world.

It seems like there’s a lot of confusion out there about exactly why the Yankees pulled Joba Chamberlain after three innings and 35 pitches today.

In case you missed it, this was a major piece of discussion before Friday’s game, when the Yankees outlined several aspects of why a change had to be being made.

So maybe it’s a good time to try and briefly recap what we know of these mysterious Joba Rules, 2009 edition:

– The old way wasn’t working. Giving him extra days of rest to combat this innings limit down the stretch appeared to have some benefits at first, but Chamberlain was 1-2 with a 8.55 ERA in the four starts that followed. The last straw was Tuesday vs. Texas, when he gave back a 4-0 lead and lost.

“It looked like it was working great,” Joe Girardi said. “He came out of
the break and was lights out. But we think that a change needed to be
made.”

– It’s the innings, not the starts. While the Yankees continue to keep this plan secretive for their own reasons, what we have established is that Chamberlain’s innings limit for 2009 is somewhere in the ballpark of 160 innings.

Generally speaking, the pitch count isn’t nearly as important, as they think a big league pitcher averages out to a 15-20 pitch inning over the course of a season — you have your quick ones and your long ones.

Girardi said that 180 is a “danger” zone, which is more than they’ve revealed about their thinking all year. Look, the Yankees don’t want Chamberlain to be their blown-out version of Bill Pulsipher, Jason Isringhausen and Paul Wilson rolled into one. I can’t blame them for being overly cautious. He’s not disposable goods.

So while the Yankees knew they couldn’t do anything with that innings limit, the way they were going to reach it is adjustable. Instead of giving him extra days, Joba will just have shorter starts for a little bit but start every fifth game.

– What about the bullpen? Is it good to use Alfredo Aceves for three innings and 32 pitches? Well, in the short term, it’s not great. But the Yankees have reinforcements coming on Tuesday as rosters expand to 40 players, and they’ll be getting bullpen help.

Sergio Mitre’s status throws a wrinkle into this that we hadn’t seen before – otherwise, you could also lean on Chad Gaudin for the backup.

If the Yankees were up by 1 1/2 games in the American League East, by the way, they wouldn’t be fooling around with this. That’s one other important point. They have a little luxury here.

- Building back up for October. One of the keys Girardi talked about was that Chamberlain must be built back up to throw 100 to 110 pitches by the end of September, so he can start in the playoffs. That tells you he won’t be turning in these three inning starts for long — not if the Yankees are expecting he’ll be ready to go seven strong innings in the postseason.

It’s a silly exercise to map out starts a month in advance, because the rotation can change, there can be rainouts, injuries, etc. Even though the Yankees didn’t pull Chamberlain because of his 35 pitches today, let’s roughly plot out that you can safely boost a pitcher by 15 or so pitches per start, Spring Training style.

Whatever the case, Sept. 4 at Toronto should give him 50 pitches to play with. If my math is right, four turns through the rotation (65, 80, 95) and Chamberlain can already be up to 110 if needed, which would fall right about the time of the last homestand of the season.

It’s frustrating to Joba; he wants to pitch and be let loose. But he understands and seems to be on board. It might work better than having him pitch on eight days rest.

“I’ve learned to be very patient over the three years that I’ve been
here,” Chamberlain said. “The Joba Rules are still going strong. I
still see the T-shirts every once in a while. But it’s better. It’s
going to make everything better in the long run.”

The Yankees have announced that X-rays taken on Yankees starter Joba Chamberlain’s right knee were negative. Officially, he is listed with a bruised right knee.

Chamberlain left his start in the first inning on Thursday after being struck with a line drive. The right-hander started his evening against the Orioles with a strikeout of Brian Roberts before Adam Jones drilled a hard line drive back up the middle, striking him near the right knee.

Yankees manager Joe Girardi and trainer Gene Monahan attended to Chamberlain on the field and initially allowed him to stay in the game after several warmup pitches.

Chamberlain then allowed a single to Nick Markakis and another hit to Aubrey Huff before Girardi and Monahan returned to the field, removing Chamberlain. He was relieved by right-hander Alfredo Aceves, who threw 3 1/3 innings of scoreless relief.