They must have moved Wellemeyer because I read earlier and they mention on Nats postgame that Tuesday was Livan vs. Lincecum.
I just checked cbssports.com and they do have Hernandez for us and Wellemeyer for the Giants.
No, I don't think they moved anyone. Tuesday is the slot for their #5. With Monday off, they could in theory skip Wellemeyer's spot in the rotation.