I heard that, and it makes sense but I would have preferred to read a quote from a Nationals official. I didn't get home in time to see him pitch, but how high stress can 52 pitches over 5 innings be?
It's also interesting that they pull him on a day where he supposedly didn't have his best stuff. Every pitcher has days like that and how pitchers adjust on off days separates good and great pitchers. It seems like a better learning opportunity than leaving him out there on days when no one can touch him.
Maybe they just wanted the pitch count low before building it up over his next two starts. Oh well.