WASHINGTON -- The Nationals placed staff ace Max Scherzer on the 10-day injured list with a groin problem.

The team announced the move Tuesday, saying it was retroactive to Sunday.

Scherzer "tweaked'' his groin in the first inning during his start on Friday. He warmed up in the outfield Monday before beginning a bullpen session, which was expected to be 31 pitches. Scherzer threw 10 pitches, then stopped, saying the groin issue prevented him from driving through his pitches.

Scherzer was scheduled to pitch Wednesday in the finale of a three-game series against the Pittsburgh Pirates. The Nationals considered pushing his start back as opposed to placing the three-time Cy Young winner on the injured list, but opted for the 10-day stint away from the field.

"For me, it was after going through the process, I just want to be more cautious than not,'' Nationals manager Davey Martinez said. "This is an injury right now that's getting better. We want it to completely get better.''

Scherzer (5-4, 2.21 ERA) should miss one start. He's been adamant the injury is minor, even hesitating to call it an injury.

Veteran reliever Justin Miller was called up from Triple-A Rochester to take Scherzer's spot. RHP Rogelio Armenteros was designated for assignment to free a 40-man roster spot for Miller.

Scherzer joins Stephen Strasburg (neck) on the Nationals' injured list. Strasburg has made just five starts this season. There is no timeline for his return. Right-handers Will Harris and Daniel Hudson and left-hander Luis Avilan are also on the injured list.