An MRI performed in Milwaukee revealed that Ben Sheets has a slight strain of his left hamstring. The Brewers held off scratching Sheets from his scheduled turn Sunday against Atlanta, but it is doubtful he will make that start. Depending on how quickly he recovers, Sheets might not pitch again this season, which would be a severe blow to the Brewers' chances of overtaking the Chicago Cubs and winning the National League Central title. Beyond the start against the Braves, he was scheduled to pitch the second game of the season-ending home series against San Diego. "It's not something you can rush," said assistant general manager Gord Ash, who oversees the club's medical program. "That's the experience with that injury. He has to feel he is ready to pitch."