NEW YORK — Bobby Jenks said he aggravated an old injury when he hurt his back Tuesday night in Yankee Stadium, but he does not expect to miss much time.

Jenks threw just four pitches after taking over for Jon Lester to begin the seventh inning. After the fourth, he was met on the mound first by catcher Jarrod Saltalamacchia, and then trainer Mike Reinold and manager Terry Francona.

It was a scene reminiscent of the one which saw fellow reliever Rich Hill blow out his elbow last week, but the Red Sox may have dodged a bullet this time around.

"It's an injury that happened years and years ago, and unfortunately it still gives me fits now and again," Jenks said. "Everything was fine once I started to cool down and the muscle started relaxing. I'll be all right, maybe a day or two."

Jenks will receive an MRI on Wednesday morning, but he said it is being done more for the "peace of mind" of the training staff. He said the muscle in question is on his left side just below his shoulder blade. He had a tear there early in his professional career and feels it from time to time, the last instance being in the past couple of years, although Jenks couldn't pinpoint an exact date.

Matt Albers took over for Jenks, who had a 3-1 count on Yankees first baseman Jorge Posada. Albers threw ball four to Posada, but then worked out of the inning to preserve the 6-3 lead.

Jenks had thrown 3 2/3 scoreless innings since returning from a one-month layoff because of a right biceps strain.