Washington Nationals pitcher Sean Doolittle Rhona Wise-USA TODAY Sports

The Nationals announced Wednesday that lefty Sean Doolittle has been placed on the 10-day injured list with a left elbow sprain. Outfielder Donovan Casey was also optioned to Triple-A Rochester with lefties Sam Clay and Francisco Perez being recalled to take the open spots on the active roster.

Doolittle’s season was off to a blazing start but will now be halted by this setback. In his first 5 1/3 innings of the campaign, he’s yet to allow a run, while surrendering only a single hit, no walks, while racking up six strikeouts. Doolittle told reporters, including Mark Zuckerman of MASNsports.com and Jesse Dougherty of the Washington Post, that he first felt something last week but that it got worse in his outing against Arizona on Tuesday. Surgery is not being recommended right now, with the plan being to reevaluate in about 10 days. That timeline suggests Doolittle won’t be able to return after a minimum stay on the IL.

Clay and Perez each made their MLB debuts last year — Clay with Washington and Perez with Cleveland. The Nats claimed Perez off waivers from the Guardians in November. Clay, 28, has thrown 5 2/3 scoreless innings in Triple-A so far this year, while Perez, 24, has 5 scoreless. With Doolittle on the shelf, they will be the club’s only two lefty options in the bullpen.

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