MIAMI — Dustin Pedroia was placed on the disabled list Saturday for the second round of the World Baseball Classic because of a strained muscle on his left side, but he said the injury isn't serious enough to keep him from being ready for opening day.

The reigning AL MVP will be replaced on Team USA's roster by second baseman Brian Roberts of the Baltimore Orioles.

Pedroia was scratched from the lineup before Saturday night's game against Puerto Rico. He said he first noticed the injury while hitting during a workout Friday, and it worsened when he hit in the batting cage Saturday.

"Obviously, I'm upset," the Boston second baseman said. "Today I felt shooting pain, so that was a sign to stop. Hopefully, it's nothing serious. I'm not concerned about the season. I'll definitely be ready for the season."

Pedroia said he'll be examined by Red Sox doctors Sunday in Fort Myers, where the team trains. He was replaced in the U.S. lineup Saturday by Mark DeRosa.

Pedroia said playing meaningful games so early in March might have contributed to the injury.

"I've never had anything like this," he said. "Maybe I pushed it a little bit too hard too fast."