The Astros closed the home clubhouse to the media for 45 minutes prior to Tuesday's game against Washington before announcing the Schafer move. Schafer began experiencing discomfort in his shoulder during the Astros series over the weekend in Atlanta, manager Brad Mills said.
"He woke up Sunday morning and his left shoulder was really bothering him," he said. "He showed up [Monday] and it felt fine, and then it progressively got worse during the game."
Schafer, who had a similar injury in 2009, was examined by team doctors Monday night before it was determined he would be placed on the DL. He's hitting .216 with four homers, 23 RBIs and 26 stolen bases, which ranks tied for sixth in the National League this year.
"Obviously you never want to go on the DL, but it's just a fact you can't have somebody down and not being able to play for an extended period of time," Schafer said. "For the best of the team it's the best thing we can do right now."
This has been a frustrating season for Schafer, who got out of the gate quickly but has struggled mightily at the plate for much of the season while battling a series of nagging injuries. He's hitting .159 (21-for-132) since June 3 with 46 strikeouts.
"It's been frustrating," he said. "The whole season's been like this after the first two months -- it's gone downhill for me and for all of us in this organization as a team. We haven't been very successful. It's sad but it's something that happens and I just need to get healthy."