The Houston Astros placed right-handed pitcher Bud Norris on the 15-day disabled list Sunday because of a sprained left knee. The move is retroactive to June 12. Norris sprained his knee pitching against the Giants on Tuesday in San Francisco. He was scheduled to start Sunday against the Rangers, but the Astros called up left-hander Dallas Keuchel from Triple-A Oklahoma City to make his Major League debut on Sunday in Norris' place. Norris, who is 5-4 with a 4.31 earned-run average in 13 starts, has not been the same since he injured his hip flexor May 31 against the Rockies. He was 5-1 with a 3.34 ERA in his first 10 starts, but was 0-3 with a 13.09 ERA in his next three starts.