Manager Davey Johnson made the announcement before today’s home game against the New York Mets.

Strasburg had a scheduled bullpen session canceled due to tenderness that remains in his lat muscle. However, he did play catch in the outfield before today’s game.

Despite a 2.54 ERA in 12 starts, Strasburg has suffered from a lack of run support this season and has a record of just 3-5. He was 15-6 with a 3.16 ERA last season when the Nationals shut him down in September after he had pitched 159 1/3 innings.

Left-hander Gio Gonzalez will be moved up a day to start in Strasburg’s original spot against the Mets.

The Nationals are already missing another member of their starting rotation with Ross Detwiler sidelined by an oblique strain. Rookie Nathan Karns was promoted from Class AA Harrisburg (Pa.) to fill Detwiler’s spot.

Johnson didn’t say precisely who will make the Saturday start against the Minnesota Twins, though he did say the pitcher will come from Class AAA Syracuse.

The move comes a day after the team placed infielder Danny Espinosa on the disabled list. Espinosa had been playing with a broken bone in his wrist, and he was batting just .158. Slugger Bryce Harper was added to the disabled list June 1 after two run-ins with outfield walls that Harper later said should have sidelined him.

Matt Slovin contributed from Washington.

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