Johnson said Rodriguez has been dealing with a lower back injury since Washington's four-game weekend series in Milwaukee, and he's been receiving treatment on it since the club returned home. Rodriguez, 1-3 with a 5.83 ERA in 35 appearances, has showed no signs of any injury. He most recently threw 38 pitches in 1 1/3 innings Tuesday against the Phillies.
"Henry's had some problems with his lower back," Johnson said. "I don't know if he exacerbated it from me throwing him 40 pitches and trying to get two innings out of him the other night, I don't know. But he has been getting some work on it.
"He's been getting treatment prior to that on his lower back. It seems like we get them in rashes around here. ... I think it was going around in Milwaukee. It seemed like everyone had a little something."
With Rodriguez down, the Nats' bullpen is back to seven players and their bench is a little deeper. Johnson said he feels comfortable with all seven of his relievers in any role, even setting up Tyler Clippard, but this could lead to more high-leverage opportunities for Drew Storen, who has been easing his way back in from right elbow surgery.
"A guy that closed 43 games last year, I have a lot of confidence in him late. He's ready for just about anything I want him to do," Johnson said. "I can kind of create matchups and stuff like that. That's the beauty of it: They're all used to going a lot."