ESPN now reports that it is simply muscle spasm and that he is day to day.

After perusing his stats, I am shocked at the disconnect between his numbers and my perception of his performance. 2.2 ERA, .9 WHIP, Better than 5 to K/BB ratio. The fact that I was distracted during the first two months of the season when he was at his best may explain the disparity. As may the blown save in a game I attended and his shitty performance in the All Star game.