He's just battling a case of strep throat and some soreness which the Nats say is normal.
Storen has thrown just two innings this spring, his last coming March 7.
"Other than the usual pitching soreness that you have during spring training, he's fine," general manager Mike Rizzo said. "He's a little under the weather the last four or five days, so we kind of sent him home the last couple days to get him out of the clubhouse."
Storen had been scheduled to throw on flat ground today, but when he came in still feeling sick, the Nats had him head home.
Once Storen is feeling better, the plan will be for him to play catch on flat ground, then throw off a mound a day later, then get a couple days off.
"I'm not really concerned about rushing him," manager Davey Johnson said. "His arm's really strong. I may not be able to do back-to-back or two innings like I'd normally like to do with a closer, but I may do that over on the minor league side. But as far as I know, the tightness has subsided and he's fine.
"He was throwing the ball really good before he got in the training room. Once he gets over this sore throat or flu, whatever he has, we'll go back to getting ready for the season. But we have a lot of time, a lot of games left. He'll get his work in. He'll be fine."