Harper grounded back to the pitcher to lead off the sixth inning and didn't run hard down the line. He also tailed off toward the dugout before reaching first base. Williams cited Harper's "inability to run 90 feet" as the reason for his benching.
The play can be seen here.
Harper, who also grounded into a double play and popped out, has been dealing with a tight quad the last few days. Williams said Harper can run the bases 100 percent but also told MLB.com on Wednesday that he wanted to be vigilant with the injury.
"It's tight on him, but we have to make sure that we are taking the right precautions so he could continue to play. We don't want to get it too bad," Williams said at the time. "The thing that Bryce has to do is make sure he monitors [the injury] himself. He has been playing a lot of center field, he has been running the bases a lot. Those are all good thing and he has done it fine."
The 21-year-old, who is a two-time All-Star, went 0-for-3 on Saturday and is hitting .295 with a .775 OPS.
The Nationals (10-8) also have an MLB-high 20 errors — including a one from second baseman Anthony Rendon on Saturday — which likely doesn't make Williams, a four-time Gold Glove third baseman, very happy. SI WIRE: Report: MLB looking to adjust home plate collision, catch transfer rules