Rapid Reaction: Blue Jays 5, Red Sox 0

TORONTO -- John Lackey's return to pitching 17 months after undergoing reconstructive elbow surgery took an awful turn Saturday afternoon, when he re-injured his right arm and immediately left the game in the fifth inning of a 5-0 loss to the Toronto Blue Jays.

The team announced that Lackey had a strained right biceps, which connotes a muscle tear. There was no word during the game on the severity of the injury.

Lackey clutched his arm in agony after throwing a 2-and-2 pitch in the dirt to Jose Reyes, who skipped over the pitch as it skittered to the backstop. Second baseman Dustin Pedroia immediately came to Lackey's side as manager John Farrell and team trainer Rick Jameyson sprinted to the mound. Lackey walked off the mound to the dugout, his arm hanging at his side.

The 34-year-old right-hander, who had last pitched on Sept. 25, 2011, in New York, had been impressive Saturday afternoon, with a fastball that touched 94 miles an hour and an assortment of breaking balls and two-seamers that kept the Jays off-balance. He struck out Emilio Bonifacio to open the fifth, his eighth strikeout of the game, but on a 2-and-2 curveball that Reyes fouled off, Lackey shook his arm in apparent discomfort. He then tried to break off a slider, with a gruesome result.

Lackey left trailing, 2-0, having given up a two-run home run to J.P. Arencibia. Alfredo Aceves replaced Lackey, and in the sixth walked two batters and gave up a three-run home run to Colby Rasmus that caromed off the facade of the second deck in right-center field. Aceves has given up home runs in each of his first two appearances; Vernon Wells hit a two-run home run off him in the second game of the season.

Aceves figures to be manager John Farrell's choice to replace Lackey in the rotation, although highly regarded prospect Allen Webster, who was so impressive in spring training, threw five scoreless innings in his Triple-A Pawtucket debut Friday night. Until the severity of Lackey's injury is determined, it is unknown how much time he will miss.

The Red Sox did not have a hit in the first eight innings after Jacoby Ellsbury's double to lead off the game against left-hander J.A. Happ. They managed just three more baserunners against Happ and two relievers, Steve Delabar and Aaron Loup. Boston's only other hit was an infield single by Dustin Pedroia off closer Sergio Santos with two out in the ninth. Rasmus went crashing into the wall to catch Mike Napoli's drive to center to end it.