Slumping Washington Nationals right-hander Drew Storen is sidelined by a broken right thumb resulting from a fit of temper, and he'll likely miss the rest of the season.

Storen hurt himself slamming the lock box on his locker in frustration after his latest outing, manager Matt Williams said Saturday. The incident happened after Storen gave up the go-ahead homer to Yoenis Cespedes in the eighth inning Wednesday, helping the Mets complete a three-game sweep.

When Storen was unable to throw Friday in Miami, he told the team what had happened, and the injury was diagnosed, Williams said.

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Storen also walked three batters Tuesday when the Nationals blew a six-run lead against the Mets, who padded their lead in the NL East with the sweep.