Last night Justin Duchscherer won his tenth game of the season. He’s 10-2 with a 1.78 ERA and a 0.88 WHIP. It won’t last; don’t think that it’ll last. But it’s interesting to analyze the guy who’s suddenly the best pitcher in baseball.

This year Duchscherer, 30, made his return to the starting rotation after spending the previous four seasons in the bullpen. He was and is best-suited to be a reliever, but, like Shaun Marcum, Justin’s having a lot of success as a stretched-out starter.

I always thought, looking at Duchscherer, that he was going to be the next Jason Isringhausen. He and Izzy are/were the same pitcher. Cut fastball in the low-90s, overhand curve. And Duchscherer was a good reliever. Aside from an injury-shortened ‘07, Justin never saw his ERA climb above 3.27 while pitching from the bullpen. And his strike out rate pulled even with the reliever’s standard: 9 Ks/9 IP.

Duchscherer’s call to the rotation is actually a very interesting story. The A’s had kept Justin in the ‘pen, thinking that his arthritic hip wouldn’t be able to stay healthy over a 150- 200-inning season. But Justin, who apparently has a slightly nervous/anxious personality, found that the uncertainty of a late-inning role aggravated his IBS–Irritable Bowel Syndrome. IBS is an extremely common disease of the gastro-intestinal system; it causes bloating, cramping, gas, and diarrhoea. It’s a twentieth-century problem, brought on by stress. And you can imagine that pitching the eighth inning for an MLB team would be kinda stressful. During the middle innings, Justin, sensing that he would have to take the mound, protect a lead, and not embarrass himself in front of a national audience, would have to leave the bench and run to the washroom.

So the A’s made him a starter, thinking that the certainty of knowing exactly when and where he was going to pitch would calm him down and ease his GI problems.

Apparently the plan’s worked.

Duchscherer’s 0.186 OBA is the most impressive number in baseball. This is a guy with a 63:21 K:BB over 101 innings. He’s pitching to contact, but no one’s squaring up his pitches. And at 88-90 mph, that’s a little strange. Which is why I think that this can’t and won’t last. Duchscherer’s minor league numbers are so far off his ‘08 pace that a correction is now long overdue. He’s always had good control (2.18 BB/9 IP), but his hit rate is almost a third below his career number (6.79 in ‘08 vs. 8.47 career). Justin has the stats of a relief pitcher, but he’s throwing the innings of a starter. That’ll catch up to him over the next ten starts.

I can’t say anything bad about Justin; he’s just the latest A’s pitcher with average stuff to post Nintendo numbers in that parking lot of a stadium. I’ll just mention one name: Chad Gaudin.

Sell high on Duchscherer. Prior to 2008, he’d never thrown 100 innings in a full MLB season. Right now he’s at 101, and it’s July 8th. If he were throwing gas and piling up strike outs, then maybe my opinion would be different. But every possible factor is against this run continuing. He’s going to tire; teams are going to see him for the second, third, fourth time; his contact rate is too high; Chavez is out, Crosby is out; his career OBA is 0.44 points above his current number.

Don’t give him away, but just know what this guy is: a great #3 starter who’s pitching like a #1. His stuff, again: 88-90 mph cut fastball with good left-right action; overhand curve and slurvey-type slider that aren’t strike out pitches, but induce bad swings. And remember his hip.