Charlie Morton left Houston's 6-2 victory over the Los Angeles Angels, who have lost five in arow, on Sunday after one inning because of discomfort in his pitching shoulder, a potential problem for the World Series champions as they attempt to win consecutive AL West titles.
The 34-year-old right-hander did not pitch for the Astros from Aug. 28 until Sept. 8 because of right shoulder discomfort. He won his first two starts following his stint on the disabled list, allowing four runs in 11 innings.
Morton threw 24 pitches in the first. He gave up a double to Justin Upton, who scored from second on a wild pitch in the dirt that bounced off the glove of catcher Martin Maldonado, who initially had trouble finding the ball.
AL West-leading Houston started the day 3 1/2 games ahead of second-place Oakland.
Yuli Gurriel hit a two-run homer, giving him three homers and 10 RBIs in the three-game series, and Evan Gattis had three hits and two RBIs.
Framber Valdez (4-1) followed Morton and struck out a career-high nine in six innings, allowing one run and three hits. He had been scheduled to start Wednesday at Toronto.
Tyler Skaggs (8-9) gave up four runs and five hits in 2 1/3 innings, the fourth straight start he failed to last four innings. Skaggs has given up 22 runs in that span.
Gurriel hit a two-run homer in the first, extending his hitting streak to nine games, and Gattis added an RBI single for a 3-1 lead.