Bonifacio, who leads the Majors with 20 stolen bases, injured the thumb while sliding headfirst attempting to steal second against the Indians last Friday. He had an MRI exam on Saturday that revealed no break.
The Marlins placed Bonifacio on the 15-day disabled list Sunday. The speedster initially felt he would only need the 15 days on the DL to recover. But a second MRI revealed a tear to the ligament, and surgery was recommended.
"I know it was very bad, but I think the reason he's going to have surgery is just to prevent future [injuries] and to make sure to attach that ligament to the bone and not have it affect him the rest of his career," Marlins manager Ozzie Guillen said. "He's going to lose a certain amount of time, but it's not a big difference. But when you slide headfirst into a base, a lot of things can happen."
The extent of the injury leaves the Marlins short two key contributors in the outfield, as Austin Kearns was placed on the 15-day DL on Thursday with a strained right hamstring.
Kevin Mattison was recalled from Triple-A New Orleans to replace Kearns. Mattison also can play center field.
"I think we have to have confidence in the guys we got. We got [Bryan Petersen] and [Chris] Coghlan, and they can cover that, obviously," Guillen said. "It happens. It's a long season. I wish I could have [Bonifacio] in the lineup, but I don't worry about that. I worry about the guys we have in the lineup."
Tom Green is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.