Welp…

Everyone knows by now that Rickie Weeks is out for the season with a torn tendon sheath in his right wrist. This is the same injury that sidelined him for awhile and subsequently irritated him until last year, and so far this season he looked to be completely healthy and fulfilling the potential he was always labeled with through his time in Milwaukee: he hit .272/.340/.517 with 8 home runs and greatly improved defensive numbers (5.4 UZR through 35 games) — his WAR so far through mid-May was only half a win lower than it was through the entire 2008 campaign.

Unfortunately he’s gone for the rest of the season, as his surgery will take 4-6 months to fully heal. To replace him, the Brewers immediately are turning second base into a platoon with Casey McGehee hitting against lefties and Craig Counsell taking care of right-handers. Since Counsell was originally slated to be Bill Hall’s platoon partner, studly prospect Mat Gamel will take care of right handed pitching at third base. There are a couple of other options the Brewers could pursue, like bringing up light-hitting Hernan Iribarren to take over second base or even signing free agent Ray Durham to try and revive his corpse. But if the double-platoon sticks, how much production will the Brewers lose with Weeks out for the rest of the season?

Weeks so far this season was hitting tremendously but I suspect he has just been seeing the ball particularly well for a stretch and was due to regress a little bit. His 19.1% HR/FB rate combined with sharp LD% and FB% increases and a low GB% implies small sample size and a return to normalcy. Combine that with a (probably) unsustainable 28.3 UZR/150, and it’s pretty clear Rickie was playing a little over his head. His updated ZiPS projections imply he would hit closer to .257/.351/.456/.808 and even if we assume the improved defense that coaches have been touting than I figure that Weeks’ defense should decline to somewhere in between his career numbers at second (essentially dead average) and where he is now (off-the-charts good). Since we’re 1/4 of the way through the season, I estimate that Weeks would be about a 5.0 WAR player for the rest of the season assuming he remained healthy. So, we lose that. But what do we gain back with the Counsell/McGehee platoon?

Counsell meanwhile is a light-stick, good-fielding utility man. He’s pretty clearly not going to keep up his current pace of batting over .300, but he has a decent career OBP (.345) which is pretty close to Weeks’ and while his offense may take a hit, Counsell has extreme value defensively, posting a career 12.9 UZR/150 at second base. Counsell is also in a platoon, meaning that he’ll only face right-handed pitching. Careerwise, he’s better against right-handed pitching, going .258/.348/.353. For the rest of the season, this approximates to about a 1.5 WAR. McGehee, on the other hand, does much better against LHP, hitting for a .796 OPS in AAA last year with 5 homers in 129 ABs, compared to a .767 OPS against right-handers. Considering the dropoff in his statistics now that he’s reached the major league level, he should put up about a WAR of 1 or so. McGehee is particularly difficult to estimate because he’s had a career 16 chances at outs at second base, so basing predictions of performance based on that small of a sample size is dangerous. I’m assuming totally average defense out of McGehee against lefties.

So far, this means that the Brewers are going to lose about 2.5 wins just from replacing Weeks with the less-able-but-still-qualified McGehee/Counsell duo.

However there’s more to the story than just replacing Rickie over at second. Remember that the move also means that the Gamel Camel to replace Counsell at third. Last night, Gamel decided to turn on a Kyle Lohse fastball and crank it to right field to drive in his first three runs and turn a close game into a punch in the gut. Gamel’s an offensive stud ready to be shown off, as evidenced by his nearly 1.100 OPS in AAA-Nashville at only 23 years old. Those numbers upon examination are excruciatingly high, but if Gamel can put up a .900 OPS in the majors he’ll be significantly outperforming Counsell’s bargain at third despite being an average statistical defender at third. Sure, he’ll give away a few horrible throws and have some fielding gaffes, but his bat is a definite improvement over Counsell. I’d estimate on the low end that Gamel’s bat adds a significant amount of WAR to the table. Since he’s predominately starting against righties, he should provide an extra 0.5-1.0 WAR for the rest of the season, assuming he remains called up at this point. To put it differently, Weeks’ loss costs the Brewers about 1.5-2 wins, and at the end of the season, that could mean all the difference when it comes to playoffs or not. We’ll see.

Of course, this is all wildly speculative and an inexact science. Estimating a two-win dropoff due to to Weeks’ departure is sure to be wrong on my part and couldn’t possibly be actually calculated until the rest of the season plays out and the hypothetical assumptions that Weeks could continue his tear at nearly the rate he was going at so far.

Enjoy the hot streak. Remember that the inevitable August and September swoon is upon us yet.