When Mariano Rivera entered last night’s A’s-Yankees game in the ninth inning to protect a two-run lead, he set yet another first in his career he did something he’s done just two other times in his career. It was the third time Rivera had ever pitched on four consecutive games in four days. I sure hope Joe’s willing to give him a day off today.

Update: Gary C notes in the comments that I misinterpreted the Baseball-Reference.com Play Index results. This is actually the third time Rivera’s thrown in four straight games. This post has been updated to reflect this information.

Remember April? It’s easy to start off an article that way, since things are so vastly different now than they were then. Now Jason Giambi is helping carry this offense. Now Melky Carbera has cooled off, to say the least. And now Chien-Ming Wang is having his bout with ineffectiveness.

During the season’s first month, Wang was 5-0, picking up his sixth win without a loss on May 2. Since then, he’s 0-2, and has seen his ERA balloon from an even 3.00 to 4.57. The “Wang is an ace” crowd was getting rather indignant in April. They’re not quite eating crow yet, but their arrogance was certainly overstated.

According to pitching coach Dave Eiland and catcher Jorge Posada, Wang’s troubles are in the form of a mechanical issue. I’m loathe to write this phrase, since it was also attributed to Randy Johnson when he came to New York, but it appears Wang is “flying open” during his delivery. This leads him to “drop his right elbow and push the ball rather than drive it down. That means no sink on his sinker and a loss of command.”

Posada notes that because he uses different arm angles for his slider and sinker, he’s having trouble moving from the former to the latter. This seems a bit strange to me. If he’s using different arm angles for specific pitches, isn’t that an easy tip to hitters? Then again, that could be another facet of his recent struggles.

So we’re getting less than expected from Pettitte and Wang, and realizing the worst case scenarios from IPK and Hughes. Yes, we’re getting far more than anyone could have expected from Mike Mussina and Darrell Rasner, but that hasn’t quite balanced things out yet. But as the offense returns to its true form, we’re going to rely on these pitchers to drive us a 15th straight playoff appearance.

In five short hours, Joba Chamberlain will climb aboard the Yankee Stadium mound and begin his tenure as a starter. We’ll have our thoughts and analysis as the afternoon goes on, but we’re not alone in assessing a move that’s made headlines among the Yankee literati for the last few months.

Today, though, the debate is flowing fast and furious, but it’s a different kind of debate. We start with Hank Steinbrenner’s predicting greatness for Joba over the next ten years. “This is about what Joba can do for us over the next 10 years,” Steinbrenner said to Pete Caldera of The Record. “That’s what we’re going to look at in a lot of way, with the new dynasty, hopefully, we can build.”

Meanwhile, as PeteAbe notes, Hank doesn’t understand innings limits. “Again, I would have perferred to start the year with him as a starter, but this is the way they have come up with,” Hank said. Always good for a quote, that Steinbrenner. I’m sure he’ll have some in-depth analysis after the game tonight as well.

Picking up where I left off this morning with claims of a mishandled transition as it relates to the bullpen, Brian, the world’s only Yankees/Flyers/Eagles fan writing at Depressed Fan, believes that the transition on the Joba end was handled poorly as well. Brian, who feels that Hank is just contributing to this circus, writes:

The problem: He isn’t ready. He can’t be. The Yankees have completely botched this transition and there’s no way he should be starting a game this soon, and there’s no way he’s ready to be stretched to 70 pitches. If I had to guess, I’d say the pressure is coming from the top down. Hank said he wants Joba to start, so they began the transition. The transition consisted of three outings of 35, 40 and 28 pitches, respectively. His previous high this season was 33. Hardly a stretch.

Yes, he followed those outings up with a bullpen session, but there was no pressure on him. Joba’s arm and his body are not ready for 70 pitches. He very well may get through 70 later tonight, but at what price? He’s going to be running on adrenaline. I can only hope he doesn’t get hurt.

I’ve toyed with this idea in my head over the last few weeks. I think it was especially glaring when Joba didn’t pitch in the extra-inning game in Baltimore and then threw just 28 pitches the next night. It seemed like the Yanks were implementing half of a plan, and now, they’re just throwing Joba into the fire for a few innings.

In the end, I have to put my faith in the Yankees Brain Trust. They know what they have in Joba Chamberlain, and they appear to know what they are doing with him. They managed to stretch him out without losing him to the Minors for ten days. I just wish today’s start didn’t have that Hail Mary feeling about it.

Via Jayson Stark:

Kei Igawa isn’t quite as buried on that Yankees’ depth chart as Carl Pavano, but it’s close. And he’s already homesick. We’ve heard from two different baseball men recently that Igawa asked the Yankees over the winter if there was any way he could return to Japan. The Yankees quietly explored their options, got nowhere and gave up. They’re still on the hook for nearly $11 million to Igawa through the 2010 season.

Now, this isn’t an original idea. RAB commenters have mentioned it; my mom has mentioned it. But how hard could the Yankees have tried to ship Igawa back to Japan?

Kyle Kendrick’s experience aside, a trade back to Japan for Igawa would be fairly unprecedented. Japanese League players — Alfonso Soriano and Hideo Nomo, I’m looking at you — have “retired” in Japan so that they could sign MLB free agent contracts, but never in the history of the game has an American team traded a player back to his home country.

At this point, it’s clear that the Yanks have just about slammed the book on the Kei Igawa Era. He has never been an effective Major Leaguer, and he’s not a part of any of the Yanks’ long- or short-term plans. He’s owed just $11 million over the next two and a half seasons, a paltry sum by Yankee standards. So why not just release him?

Well, the Yanks don’t want to let him go because they’re afraid that some other team will pick him up for the league minimum and catch lightening in a bottle. By now, though, considering that the Yanks have even explored sending him back to Japan, it’s clear that Igawa is nothing more than a warm body to fill space at AAA. He’s probably going to end his brief American career as the highest-paid AAA starter ever, but that’s better than watching him get shelled in the Bronx.

The next stop on the Joba train comes on Wednesday. The soon to be starter will aim to throw 50 to 55 pitches in relief against the Orioles, hopefully with a bit more economy than Saturday, where he threw 40 pitches (22 strikes) over two innings of work. After that, though, the Yanks might run into an issue: You can’t count throwing more pitches than that out of the bullpen, even if Mussina is the starter.

This would create an interesting scenario for the starting rotation. Namely, who do you axe in favor of Chamberlain? If he’s going to start a game, it’s best not to screw around. After throwing 55 pitches on Wednesday, he should be on tap to pitch Monday (five days’ rest), and certainly no later than Tuesday. With the off day on Thursday, the Yanks will have some juggling to do.

Kennedy is going tonight, and Pettitte is going tomorrow. That much is set. Clearly, a lot rides on Kennedy’s outing. He’d be the clear choice for removal from the rotation. If that were the case, you’d probably see Mussina go Friday, Wang go Saturday, Rasner Sunday, and Joba Monday, possibly with Kennedy shadowing him. The alternative there is to swap Kennedy for Karstens and have the latter shadow Joba.

If Kennedy pitches well tonight, though, it makes little sense to remove him from the rotation. Girardi has not ruled out a six-man pitching rotation, so pushing everyone back a day is an option. That would allow Joba some more time in between starts, and also help keep his innings in check for the rest of the season. The only drawback, of course, is that you’ll get fewer appearances from Wang. That’s an issue that certainly needs to be addressed.

The only issue I have with a six-man rotation is the bullpen. Are the Yankees prepared to only have six guys coming out of the pen? Recent history says they are not. As with many other potential moves, this could spell the end of Morgan Ensberg — and of Jason Lane, if the team decides to use Ensberg’s roster spot for a reliever rather than another position player.

Clearly, though, this is a good problem to have. As they say, you can never get enough good starting pitching.

With Joba’s needing more work now that he’s on the way to the starting rotation, the Yanks will juggle pitchers this weekend. Mike Mussina, coming off of a long 0.2 inning outing, will pitch on short rest on Saturday with Joba coming in for three innings in relief. Chien-Ming Wang and his aching calf will get an extra day of rest, and the Yanks’ ace will pitch the Sunday game on a week’s rest. His sinker may be up with so much time off so look for his secondary pitches at the outset.

It’s old news by now: The process of converting Joba Chamberlain back into a starter has begun. There’s not much debate that the rotation is where Joba belongs, no matter what George King and Steve Phillips say. Your best arms should pitch the most innings, period. Case closed. End of story.

Lots of Yankees’ fans haven’t been exposed to Joba the starter, while others forgot just how great he was in that role. Well, if you’re one of those unfortunate people, I’ll show you how great the kid can be as a starter: I dug through the DotF archives and compiled Joba’s 2007 game log from his time in the rotation. The good … no wait … great stuff starts after the jump.

Started the year with High-A Tampa

May 7th: 4 IP, 3 H, 0 R, 0 ER, 0 BB, 5 K, 4-3 GB/FB

May 12th: 5 IP, 0 H, 0 R, 0 ER, 4 BB, 6 K, 4-4 GB/FB

May 17th: 5 IP, 5 H, 3 R, 3 ER, 1 BB, 5 K, 1 WP, 1 HB, 6-4 GB/FB

May 22nd: 6 IP, 4 H, 2 R, 2 ER, 2 BB, 7 K, 9-1 GB/FB

May 27th: 8 IP, 2 H, 0 R, 0 ER, 2 BB, 9 K, 9-5 GB/FB

June 2nd: 7 IP, 5 H, 3 R, 3 ER, 2 BB, 10 K, 1 WP, 8-3 GB/FB

June 7th: 5 IP, 6 H, 1 R, 1 ER, 0 BB, 9 K, 2-3 GB/FB

Promoted to Double-A Trenton

June 12th: 5 IP, 3 H, 0 R, 0 ER, 2 BB, 9 K, 4-2 GB/FB

June 17th: 6 IP, 3 H, 1 R, 1 ER, 1 BB, 8 K, 2 HB, 3-7 GB/FB

June 22nd: 5.2 IP, 5 H, 5 R, 5 ER, 3 BB, 9 K, 2 WP, 3-4 GB/FB

June 28th: 5 IP, 5 H, 2 R, 2 ER, 4 BB, 10 K, 1 WP, 2-3 GB/FB

July 3rd: 6 IP, 4 H, 0 R, 0 ER, 1 BB, 12 K, 5-1 GB/FB

July 14th: 7 IP, 3 H, 0 R, 0 ER, 1 BB, 9 K, 7-5 GB/FB

July 21st: 4.2 IP, 9 H, 7 ER, 3 BB, 7 K

Promoted to Triple-A Scranton

July 26th: 5 IP, 4 H, 0 R, 1 BB, 10 K

Joba was shifted to the bullpen shortly after his July 26th start. When you go through and add up his stats as a starter, you get this pitching line:

84.1 IP, 61 H, 24 ER, 27 BB, 117 K

That works out to a 2.56 ERA, 1.04 WHIP, 12.49 Kper9, and 4.33 K/BB. He had double-digit strikeouts in 4 of the 15 starts, and 9 strikeouts in 5 others. He held the opponent scoreless in 7 of the 15 starts, and only twice did he allow more than 3 runs.

Small sample size yes, but his sample as a reliever is even smaller.

Not only did the Joba kerfuffle overshadow a solid Yankee win, but lost in the frenzy was some alarming news concerning Yankees ace Chien-Ming Wang. The righty suffered a calf strain on Sunday night against the Mets and kept pitching — poorly, at that. An MRI revealed a very slight tear, but the Yankees trainers and Wang say he is set to make his next start, for now. This is not an injury the Yanks can afford.

During his postgame interview with Kim Jones, Joe Girardi fielded a question about Joba’s throwing a career-high 35 pitches tonight. His response: “The process has started.” That process, of course, is turning Joba from a reliever back into a starter. Girardi, in announcing one of the more significant in-season moves the Yanks will make this year, was very matter-of-fact about it. So here it goes…

Update: Courtesy of Mike’s DVR, we have a transcript:
Kim Jones: What are we to read into it, Joe, that Joba pitches two innings and it looked like he started the ninth with a couple of change-ups?
Joe Girardi: Well, the process has started converting Joba to a starter, and tonight was the first [time] extending him a little bit, and we’ll continue to do it and get him up to where he can throw enough pitches.

As the Yankees — without Jorge Posada and Alex Rodriguez’s anchoring the middle of their lineup — struggle to score runs, the team has come to rely upon their starting pitching to keep them in games. While the back end of the rotation has been in flux, Chien-Ming Wang and Mike Mussina have so far done their jobs and both lead the team with six wins. Where the Yanks’ pitching has faltered, however, has been with Andy Pettitte.

Over his last five starts — a period of time that seems to correspond with the Yanks’ less-than-stellar hitting — Pettitte has not been his reliable self. He’s put together a truly forgettable stretch of pitching. Over 27.1 innings, he’s given up 35 hits, five of them home runs, and nine walks while striking out 24. He’s 0-4 over that span with a 6.26 ERA. Yesterday’s Pettitte effort counts as a Quality Start, but he’s probably just as unhappy as the rest of us were with his forcing in a run by walking the Mets’ number eight hitter with two outs.

During this stretch of time, opponents are hitting .315 off Pettitte with a .372 OBP and a .477 slugging. Basically, with Pettitte on the hill, opposing hitters are putting up Magglio Ordoñez-like numbers. That’s not going to lead to many Yankee wins.

For Pettitte right now, the key stat seems to be the batting average on balls in play or BABIP. Over the course of the season, Pettitte’s BABIP is .333 while a pitcher will, on average, see a BABIP of .290. For the Yankees, this is good news. Luck dictates that Pettitte will stop giving up so many hits at some point soon. He’s bound to regress to his career mean and become a more effective pitcher.

But at the same time, Pettitte’s defensive-dependent pitching numbers raise something of a red flag. His line drive numbers are down this year and his fly ball numbers are down this year but he’s giving up many more groundballs — 53.3 percent of all balls put in play this year compared to 47.7 percent last year — than he has in the past. The Yankee defense, then, isn’t doing a very good job of turning the ground balls Pettitte is surrendering into outs.

Something has to give here, and it will. Petttitte’s BABIP will decline, and the Yanks will hopefully grab a few more batted balls. The team certainly needs Pettitte to be more effective than he’s been over the last month. The success of their starting pitching depends on it.