OAKLAND, Calif. – He nearly turns his back to the batter as he winds up, then whirls forcefully forward, using an exaggerated stride toward the plate to generate velocity as he releases the ball. If you were a coach teaching proper pitching mechanics, you would erase all video of Caleb Thielbar's delivery, for fear kids would emulate his violent motion.

Wait, bad choice of words. "I don't know if I'd say it's violent — it's explosive," Thielbar said. "But the Twins didn't try to change it. They've embraced it. And it's worked out."

It has, probably because of his unusual windup, not despite it. Thielbar hasn't had a season as statistically successful as last year, except when it matters. His ERA of 3.13 is significantly higher than last year's 1.76, but it's due almost entirely to a four-game slump in mid-May, when his control was out of whack. Remove that bad week, and the 27-year-old from Randolph, Minn., is at 1.95 this season.

More importantly, he is pitching in significantly more critical situations this year, mostly against lefthanded batters, and he's rewarding the Twins' trust. Thielbar has held hitters to a .186 average in "high-leverage" or "medium-leverage" situations, when the game is at stake.

Not bad for a guy the Brewers released before he climbed any higher than Class A.

That unusual delivery is the reason why. When he was drafted, the Brewers did an evaluation of his mechanics, "and they said I was going to have some shoulder problems if I kept throwing that way," Thielbar said. "They changed how I threw, and I lost 6 miles per hour immediately, and ended up getting released."

He went back to his old delivery when the Twins signed him off the St. Paul Saints roster, and he has stuck with it.

"When he came over, we said, '[Do] you always throw like that?' He told us the story, but if you ask hitters or catchers about him, they'll tell you he's very deceptive," Twins pitching coach Rick Anderson said. "One thing with pitching, you always love deception. You can get by with lesser stuff if you keep the hitter from seeing the ball. And that's him. I would never change it."