BOSTON — Jacoby Ellsbury, the Sox’ exciting rookie outfielder, was forced out of the game because of a strained right wrist, suffered while making a spectacular diving catch in right-center in the fourth inning.

Ellsbury, who moved from left field to center field when Coco Crisp was ejected for his part in a second-inning bench-clearing brawl, went a long way across the outfield in tracking down Evan Longoria’s leadoff drive in the fourth.

He made an all-out dive, fully extending his right arm and snaring the ball an inch or two about the turf. As he made the catch, though, his glove stuck in the grass briefly, enough to bend back his right wrist as he rolled over it.

Ellsbury held on to the ball and quickly took off his glove, flexing the fingers on his right hand, in obvious discomfort. Manager Terry Francona and trainer Paul Lessard went out to right center to check on him.

After a while, Ellsbury walked off the field with Francona and Lessard. X-rays taken at the park were negative and he will be evaluated today.

Ellsbury’s injury left the Sox thin in the outfield. Crisp was gone, Chris Carter had already been summoned from the bench, and Manny Ramirez was resting his sore hamstring by serving as the designated hitter.

So Kevin Youkilis came off the bench and played right field, with J.D. Drew moving from right to center.

If the Sox lose Ellsbury for any length of time, they’ll be minus power ( David Ortiz, left wrist) and speed (Ellsbury), not to mention a likely suspension coming for Crisp.

Francona, though, seemed optimistic that Ellsbury will be able to return soon.

After Ellsbury’s injury, outfielder Brandon Moss was taken out of Pawtucket’s game in Charlotte in the third inning last night. Francona said Moss would be added to the roster today. Carter will be returned to Pawtucket.

skrasner@projo.com