The medical staff of the Cubs is keeping a close eye on the right shoulder of pitcher Carlos Zambrano after he complained of stiffness in the area, according to The Chicago Sun-Times.
It isn't considered serious, but the team remains cautious about the potential injury.
He pitched in a no-decision on Saturday against the Pirates, giving up four earned runs in four innings, but the shoulder issue wasn't thought of as a cause.
Zambrano is 6-1 with a 2.45 ERA this season.
Zambrano's Stiff Shoulder Worries Cubs