Oakland Athletics pitcher Jarrod Parker left Saturday's game against the St. Louis Cardinals in the fourth inning after collapsing on the mound. John Hickey of Bay Area News Group tweeted that the injury was "hamstring tightness," according to the team.
Parker, 22, allowed just one hit through the first three innings, before giving up a double to Cardinals right fielder Allen Craig on the play he was injured. He was replaced in the game by Jesse Chavez, who gave up four earned runs in 1 1/3 innings en route to a 7-1 loss for the Athletics.
After earning a 13-8 record in his rookie season and finishing fifth in the American League Rookie of the Year voting, Parker has a 6-6 record in 2013 and a 4.11 ERA. He was picked ninth overall by the Arizona Diamondbacks in the 2007 amateur draft, but was traded to Oakland in December 2011.