Matsui left Sunday's game at Tampa Bay due to a strained right hamstring. He suffered the injury during his at-bat in the sixth inning while facing Rays lefty Scott Kazmir.
"He is DL'd officially," Astros manager Cecil Cooper said. "David Newhan will take his spot."
"It's at least a couple of weeks," Cooper said. "We don't know [how long] yet."
For Matsui, who is batting .271 in 57 games, it is his second stint on the DL since the Astros signed the free agent during the offseason. He missed the first 16 games of the season.
Mark Loretta took Matsui's place at second base and in the second spot in the order Tuesday night against Texas.
Jim Molony is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.