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Prior to their game in Oakland on Thursday night, the Yankees are expected to place All-Star starting pitcher Nestor Cortes on the injured list due to a groin injury, reports The Athletic. As a corresponding move, right-handed reliever Greg Weissert will be called up from the minors to join the roster. 

Cortes, 27, is enjoying a major breakout season. Through 23 starts, he's 9-4 with a 2.68 ERA (143 ERA+), 0.96 WHIP and 133 strikeouts against 33 walks in 131 innings. He's posted a 3.4 WAR, good for eighth among AL pitchers. 

There's no word just yet on how much time Cortes is expected to miss, but it's a big blow to the Yankees. If nothing else, they are lacking for rotation depth right now. 

Gerrit Cole, Domingo Germán, Frankie Montas and Jameson Taillon are their four remaining starting pitchers. Lefty Jordan Montgomery was traded to the Cardinals at the deadline. Luis Severino is injured and likely out until late September. They've been dealing with a handful of injuries in the bullpen, too, further compounding the issue. 

If the Yankees need to plug someone into Cortes' spot for multiple starts, it looks like right-hander Clarke Schmidt. He's made a spot start at the big-league level this season. His other 16 big-league appearances this season have come in relief, but he recently made three starts in the minors -- going five innings, six innings and 4 2/3 innings, respectively -- and he threw 60 pitches in three relief innings Tuesday against the Mets

Schmidt, the Yankees' 2017 first-round pick, has a 2.18 ERA in the majors this season and has had good success as a starter in Triple-A (2-1, 3.27 ERA, 1.06 WHIP, 46 strikeouts, nine walks, 33 innings). 

A few days ago, the Yankees were a brutal 4-14 in August and had seen their once-15 1/2 game lead in the AL East shrink to seven games, but they've now won three straight games ahead of Thursday's series opener against the A's.