(CBS/AP) — White Sox pitcher Jake Peavy will miss 4-6 weeks after an MRI has revealed a fractured rib in his left side.

The injury forced Peavy to leave last night’s start against the Seattle Mariners early, pitching just 2 1/3 innings and giving up six earned runs. Peavy felt something wrong in his ribs when he was playing catch a day before his start. Still, he thought he could pitch through the discomfort.

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After the game, Peavy said it was difficult to even take a deep breath. He had X-rays at the stadium that were inconclusive, leading to the MRI exam.

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The right hander is 6-4 with a 4.30 ERA in 11 starts.

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