Zambrano was hit in the head by a line drive and sustained soft tissue damage, according to a major league source. The Cubs pitcher is slated to undergo more tests in the coming days.
Zambrano received 18 stitches after being hit on the side of the mouth, according to his agent Barry Praver. Zambrano will visit his doctor in a week, Praver said, before resuming his winter ball pitching.
After Zambrano was hit by the liner, he picked the ball up, registered the out and then, in typical Zambrano style, pointed to the sky.
Zambrano was making his third winter league start for Caribes de Anzoategui of the Venezuelan winter league Friday. He asked the Cubs' permission to play in Venezuela this winter.
"He's a bull," Caribes general manager Sam Moscatel told the Chicago Tribune on Saturday. "He's OK. We spoke (Friday) night after he had the surgery, and he said he wants to make his next start on Friday."
This past Monday, Zambrano flew back to Chicago to meet with new Cubs' president of baseball operations Theo Epstein. Zambrano was told there was a path back to the Cubs in spite of his tumultuous past.
"We said he'd have to work hard and that we aren't welcoming him back unconditionally," Epstein said of this week's meeting with the embattled starter. "We said he'd have to earn his way back."
Zambrano returned to Venezuela on Tuesday.
Bruce Levine covers the Cubs for ESPNChicago.com.