(Photo credit: Ed Szczepanski-Imagn Images)

The Houston Astros, fighting to maintain their lead in the American League West, could be facing a key absence after Jose Altuve sustained a foot injury on Tuesday in San Francisco.

The star second baseman was plunked by an 82 mph curveball from Giants left-hander Carson Whisenhunt.

Altuve stayed in the game before leaving in the middle of the second inning. Nick Allen took over at second base.

Following Houston's 4-1 loss, Astros manager Joe Espada said preliminary scans on Altuve's foot were negative but that more testing would be done on Wednesday.

Altuve said postgame, 'I wanted to go and play defense to see if it gets better, but it was getting worse. I didn't want to do anything stupid, so we decided to come out of the game.'

Asked about the chance of him playing in the series finale Wednesday afternoon, Altuve said, 'Maybe I go to sleep and wake up and (I'll) be able to play. The thing is, if I'm able to play, I'll be out here. I don't want to take any days or waste time, but it is what it is.'

Altuve, a nine-time All-Star, is struggling through one of the worst seasons of his career. He is batting .240 with a .304 on-base percentage, a .391 slugging percentage, 13 homers and 35 RBIs in 96 games.

After an eight-game run from July 28-Aug. 5 in which he hit .394 and had six multi-hit games, Altuve is 2-for-14 (.143) in his past five games.

A two-time World Series champion and the 2017 American League MVP, Altuve has a career .300/.358/.463 batting line with 268 homers, 924 RBIs and 327 stolen bases in 2,072 games.

The Astros hold a half-game lead over the Rangers in the AL West after both teams lost on Tuesday.

--Field Level Media