Houston Astros starter Cody Bolton left Sunday's 6-1 loss to the Seattle Mariners in the second inning because of mid-back tightness. During his first major league start last Monday, Bolton was hit on the back by a 102.5 mph line drive, but still threw 4 1/3 innings in a 9-7 loss. Bolton (0-1) walked his first three batters in the second inning Sunday, then was joined on the mound by Astros manager Joe Espada and an athletic trainer.