The Red Sox on Wednesday activated veteran knuckleballer Tim Wakfield from the 15-day disabled list. Wakefield, who had been sidelined since July 20 with a rib cage injury, will start the middle contest of a three-game series against the Orioles later Wednesday. Expected to only miss three weeks when he was placed on the disabled list, Wakefield was one of a number of key injuries that led to the Red Sox's swoon in the second half, taking them from 2 1/2 games up in the American League East to 10 1/2 behind the Yankees.