The outfielder played three innings in center field on Friday as he recovers from a concussion he suffered last week.
The Nationals' manager is thinking about his team's psyche, but at least publicly he's not ready to panic about their sloppy play.
Matt Williams compared Blake Treinen's fastball to Justin Verlander's.
Gio Gonzalez vs. Michael Wacha.
The catcher took five "nice and easy" swings with a bat on Friday and was happy to have a bat back in his hands.
The Nationals called up lefty Xavier Cedeno, giving them a fresh arm after Blake Treinen carried a heavy workload.
Ian Desmond has bounced back from vicious defensive slumps before, and he must try to again.
The issue has come up twice already for the Nationals but it doesn't mean players are happy with the new interpretation.
Denard Span expects to come off the seven-day DL on Saturday after a successful rehab game.
After an early slump, Harper is 14 for 29 with four walks, five extra-base hits and six strikeouts, and has an eight-game hitting streak.