Washington Nationals slugger Bryce Harper was injured on this slide into third base. (AP Photo/Nick Wass)
Washington Nationals left fielder Bryce Harper will have surgery Tuesday to repair a torn ulnar collateral ligament in his left thumb and is expected to be out until at least early July, reports ESPN.com's Keith Law.
Harper, 21, was already on the 15-day disabled list because of the thumb injury.
Harper was injured when he slid head-first into third base after a bases-clearing triple in Friday night's victory over the San Diego Padres, but stayed in the game for an inning and then was replaced.
Los Angeles Angels outfielder Josh Hamilton is out with the same injury stemming from a similar head-first slide into first base earlier this month.
The oft-injured Harper missed 44 games last season because of a left knee injury.
Harper is hitting .289 with one home run and nine RBI in 22 games this season.
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