Will Middlebrooks Injures Left Hamstring, May Leave Hole at Third Base for Red SoxThe Red Sox got the upper hand on the Mariners on Sunday, beating them 2-1 in 10 innings, but it came at the cost of another injury.

Will Middlebrooks left the game after hurting his left hamstring while stealing second base in the ninth inning, Nick Cafardo of the Boston Globe reports. The injury could sideline Middlebrooks for a bit if it is a tear or worse.

With Kevin Youkilis gone in a trade to the Chicago White Sox just last week, the Sox now have only Nick Punto and Brent Lillibridge — acquired in the trade — available to help at the hot corner. Cafardo speculated that Boston could look to start trading, as the Sox have an excess of outfielders.

Middlebrooks had hamstring issues earlier this season, including tightening that led him to sit out a few games.

Manager Bobby Valentine said the medical staff would look at Middlebrooks on Monday morning, and that Middlebrooks may not be cleared to play at least Monday night against the Oakland A's, depending on the results.