Aaron Cook to Start Saturday While Josh Beckett Deals With Lat Muscle Stiffness

BOSTON –– Aaron Cook has received his promotion. Now, he'll be rewarded with a start Saturday against the Orioles.

Before Wednesday's game against Oakland, Red Sox manager Bobby Valentine announced that Josh Beckett –– who was originally slated to start Saturday –– was experiencing stiffness in his right lat muscle.

"Josh is going to just miss that one start to play it safe on the fact that he threw more pitches than he's normally throwing," Valentine said. "It's the next day stiffness that just was a little more than normal."

For now, Red Sox general manager Ben Cherington doesn't believe Beckett will need a stint on the disabled list. Still, the right-hander's injury opened up an opportunity for Cook to capitalize on, after drawing rave reviews in the minors.

"When he was at Pawtucket, he's been able to hold that sinker deeper in the pitch count," Cherington said. "That's the key for him obviously is letting that sinker play and getting groundballs."

With a stretch of 20 games in 20 days looming, Cherington hadn't ruled out the possibility of employing a six-man rotation. So while Saturday will be Cook's first start, it may not be his last.

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