The bat shattered during catcher Welington Castillo's at-bat during the Cubs' contest in Florida on Sunday. Colvin was running down the third-base line when a portion of the bat punctured his chest.
"I feel really bad about it," Castillo said. "It wasn't on purpose, but he's my teammate. I hope he's getting better."
A Cubs spokesman said Colvin was in stable condition at Jackson Memorial Hospital and is expected to remain there for the next few days for observation.
The portion of the bat hit him in the upper left side of the chest. It punctured but did not stick in his chest. Doctors are taking X-rays on Colvin's chest, and there's a suture on the wound. The team said there was minimal external bleeding. Colvin was being treated with a chest tube to prevent a collapsed lung.
"It's scary, that's the danger of a maple bat," Cubs infielder Jeff Baker said. "Thank goodness he's OK."
While ash bats usually splinter into smaller pieces, maple bats have a tendency to shatter into larger chunks.
"These bats, I'm amazed it doesn't happen more," Cubs manager Mike Quade said. "We have seen guys get hit with pieces, but to actually get stabbed with one, I just don't ever remember [seeing it]."
Colvin went 0-for-1 with a walk and an RBI in the Cubs' 13-3 win.
The right fielder is expected to miss the rest of the season. He hit .254 with 20 homers and 56 RBIs in his first year in the majors.
Bruce Levine covers the Cubs for ESPNChicago.com. Information from The Associated Press was used in this report.