The Nationals scratched Bryce Harper from the lineup on Sunday:

Harper exited the Nationals’ 7-1 loss to the Giants in the sixth inning Saturday with a stiff neck. He had struck out three times. He appeared to be in pain after fouling off a pitch during his second plate appearance in the third inning and a trainer came out to check on him.

I saw that painful foul, and F.P. Santangelo commented at the time that you never know when someone is playing through a injury. In other words, it looked like something that had been bothering Harper for a while rearing it’s ugly head.