Ramirez led off the sixth inning with a walk against Barry Zito, then tried to advance to third base on a single to right field by A.J. Ellis. But between second and third base, Ramirez pulled up and slowed down, and appeared to favor his left leg.
Ramirez was helped off the field by team trainers, and replaced in the bottom of the inning by Justin Sellers at shortstop.
Friday was just the third start this season for Ramirez, who was activated from the disabled list on Monday after missing 24 games with a torn right thumb ligament. Ramirez is hitting .455 (5-for-11) with a home run on the season, and now he just adds to the growing list of Dodgers injuries.
The Dodgers are already in limbo with second baseman Mark Ellis (strained right quad), who missed his sixth consecutive game Friday night; and Carl Crawford (tight right hamstring), missing his third straight. Even first baseman Adrian Gonzalez got into the act, as he was a late scratch Friday night with neck pain.