MLB.com: [Dontrelle] Willis leaves with hyperextended knee

Tigers starting pitcher Dontrelle Willis left his start Friday night against the White Sox with a hyperextended right knee after slipping off the mound.
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The game started on schedule in light showers after heavier rains passed through prior to the game. Grounds crew workers applied drying compound to the mound after taking off the tarp just before game time.

Willis walked leadoff man Carlos Quentin before he slipped off the mound while trying to deliver his first pitch to Orlando Cabrera. Willis stretched out on the mound and grabbed the back of his right knee as manager Jim Leyland and head athletic trainer Kevin Rand came out of the dugout.

Willis stayed in the game after some warmup pitches, but he proceeded to walk Cabrera. With two on and no outs, Willis fell behind Jim Thome, including a wild pitch in the dirt that advanced both runners and put Thome in a 2-1 count.

That’s when Rand and Leyland came to the mound again.