McCutchen had a bruise on the back of his neck, and X-rays were negative.
McCutchen was struck by a 90 mph fastball from Mike Leake as he ducked and partially turned his head.
The Pirates' leader in runs and stolen bases remained on the ground over home plate for several minutes while team trainers attended to him.
McCutchen walked slowly off the field on his own power but looked somewhat disoriented and was aided by someone on each side.
The next half-inning, Pirates starter Paul Maholm hit Leake in the knee with a pitch, prompting a warning to both teams by home plate umpire Dana DeMuth.