As much as the Angels' tenuous playoff hopes rest on Albert Pujols' bat, his legs could put a severe strain on those postseason chances.

Pujols had hits in each of his first two at-bats as the Angels beat the Boston Red Sox, 7-3, on Wednesday night. But Pujols left the game after his fourth-inning double when he felt tightness in his right calf while running the bases.

He will undergo a precautionary MRI to determine the extent of the injury Thursday.

"I'm feeling pretty sore right now," Pujols said after the game, a rare admission from a player who has missed just four of the Angels' 124 games this season and leaves the lineup only reluctantly.