Well, he is. Kind of. Hopefully not seriously -- but serious enough to miss a turn in the rotation. From Nats.com:

According to the Nats.com report, the club won't fill Bergmann's spot by rushing a young pitching prospect "such as Collin Balester and Cory Van Allen" -- which is both a relief and quite laughable, especially in the case of Van Allen, who is currently hurling at Class-A Hagerstown. According to the article, "it most likely will be a veteran pitcher getting the call" -- meaning we could be seeing the triumphant big league return of Tim Redding, our presumptive No. 2 guy at the start of the spring -- or perhaps Billy Traber, who's pitched a couple relief innings since making his way from Columbus. Speculation aplenty can be found at Nationals Journal (and Barry Svrluga emphasizes the It's Just Precautionary, Bergmann Could Pitch But It Was Considered Unwise angle).

For the record, I vote Traber. But either way it's dumb flippin' luck, though Harper might preemptively dispute that characterization.