The look on Chase Headley's face spoke volumes.

The normally smiling third baseman was in a bad mood after Wednesday's rain-shortened game in Boston and his disposition hadn't improved much by Friday afternoon.

Although the Padres won a second straight game in Boston in Wednesday's horrible conditions, Headley suffered an injury during the game's last at-bat that kept him on the sidelines Friday night with a sore shoulder.

"Hopefully this is only for a day or two," Headley said. "But I'm not happy."

The last player to hit before the game was called in the middle of the eighth, Headley's rear foot slipped in the muck of the batter's box as he swung.

The awkward swing tweaked a shoulder injury that Headley suffered two weeks ago when he and shortstop Jason Bartlett tripped over each other while chasing a foul pop fly down the left field line at Petco Park.

"I hope this blows over," said Padres manager Bud Black. "We're going to keep an eye on it and not push it."

Headley is one of the Padres' hottest hitters.

Last week he became the first Padre in history to have three four-hit games in a span of six games. He is hitting .327 since May 1 and has the fourth-highest average in the National League (.338, 49-for-148) since May 11.