Just when the Texas Rangers were beginning a push for a postseason spot, one of their stars went down for an unusual reason.

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Shortstop Corey Seager had an appendectomy Thursday, a procedure that isn’t exactly career-threatening but was a jolt in a sport more used to arm and leg problems. It’s not clear how long Seager will be out. His season could be over, or he might be able to return in a couple of weeks.

The Rangers have won five straight games to pull within 2 1/2 games of the division rival Seattle Mariners for the last wild card in the American League. Texas now has the third-best run differential in the AL, thanks in part to a 20-3 win over the Los Angeles Angels this week in the team’s last game before Seager’s operation.

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Everyone knows how dangerous Bruce Bochy’s team could be if the four-time World Series-winning manager can get the Rangers in the postseason, but as well as they’re playing right now, they’re also losing key players at an alarming rate. In addition to Seager, second baseman Marcus Semien went on the injured list recently after fouling a ball of his foot. Right-hander Nathan Eovaldi, who is 11-3 with a 1.73 ERA this year, went on the IL because of a strained rotator cuff.

Texas, which has the best ERA in baseball, is one of a small number of teams on the postsesaon bubble at the moment. According to FanGraphs, 10 teams have a probability of reaching the playoffs of at least 90%, and 16 are below 10%. The four in between are all in the AL — Houston (88.5%), Seattle (87.1%), Texas (14.3%) and Kansas City (10.9%). That group includes three teams vying for the AL West title, and all four are in the mix for a wild card.

Seattle Mariners’ Jorge Polanco showing a good sign at the plate