OAKLAND -- A's infielder Arismendy Alcantara has been ruled out for the rest of the season because of a sprained thumb.
A's manager Bob Melvin said Friday that the injury stems from when Alcantara attempted to steal second base in the ninth inning of Oakland's 6-5 loss to the Astros on Wednesday.
"They're going to put it in a cast. Hopefully there's no surgery," Melvin said before the A's began their final home series of the season against the Rangers. "Just need some time for it to heal up."

The injury concludes what has been a rocky season that included several different stops for Alcantara. After being acquired by the A's in a trade with the Chicago Cubs in June, the 24-year-old had four stints with Oakland.
His longest stay with the Major League club came in September, thanks to expanded rosters. During that time, Melvin felt Alcantara best showcased his versatility while coming off the bench. Alcantara appeared in nine games this month, recording two RBIs, two runs and one stolen base.
"He's a very athletic kid with a lot of versatility," said Melvin. "Very seldom do you find guys that can play in the middle of the infield and also in the outfield. He runs well, he switch-hits. He got off to a little bit of a slow start with the bat, but seemed to be swinging the bat better with us, and certainly in Triple-A , the numbers were good towards the end as well.
"What he can do off the bench, moving around the outfield, pinch-run opportunities. When you're in September, guys like that are invaluable. We'll miss him here with the last 10 games of the season."
Melvin does not expect this setback to have any affect on Alcantara's outlook for 2017.
Vogt wins Jim 'Catfish' Hunter Award for third straight year
A's catcher Stephen Vogt was presented with the 2016 Jim "Catfish" Hunter Award before the club's game against the Rangers on Friday. Vogt is the first player in history to become a three-time winner of the honor recognizing the A's player whose play on the field and conduct in the clubhouse best exemplifies the courageous, competitive and inspirational spirit demonstrated by the late Hall of Fame pitcher.
"To get it three years in a row, I'm completely blown away," Vogt said of the honor, which is voted on by A's players, coaches and staff.
Vogt, who entered Friday batting .254 with a career-high 28 doubles, added that winning three years in a row carries extra weight, given the amount of turnover the club has experienced.
"It's basically three different groups of people," he said. "I'm humbled, I'm honored. To have your teammates think of you in this light is the highest honor you could receive."
"It's not a surprise to anybody that is in our clubhouse," said Melvin. "As far as tenure goes here , he's one of the guys with the most tenure. He's always been very vocal, has a lot of leadership qualities. I know he's proud of that. We're proud of the fact that he won it again."