The Nats could be without the productive bat of Adam LaRoche for an extended time. (Photo by John McDonnell/The Washington Post)

Adam LaRoche underwent an MRI on his troublesome right quadriceps muscle  Saturday and the Nationals are considering placing the first baseman on the disabled list, Manager Matt Williams said.

Williams said the Nationals will evaluate the situation with doctors and announce the results of the MRI after Saturday’s game. LaRoche, the Nationals’ most productive hitter this season, has been dealing with the quad strain for two weeks.

Through 35 games, LaRoche, 34, has posted a 158 OPS+, which is adjusted to the ballparks. That figure ranks 10th in the major and tops on the Nationals. He is hitting .319/.421/.504 with five home runs and 21 RBI. Williams had originally hoped for LaRoche to play first base on Saturday, but Kevin Frandsen is instead for the second straight game.

LaRoche served as the Nationals’ designated hitter in Friday’s game and left the game in the seventh inning, after two at-bats. At first, LaRoche wasn’t sure if being the DH and sitting in between at-bats would be beneficial, as it would allow the muscle to tighten up. But before Friday’s game, he said he would ride a stationary bike and apply a heat pad between at-bats. Still, he was not able to get through a full nine innings.

“When he gets a base hit, he can monitor himself when he’s running,” Williams said. “But the first two steps playing defense can be difficult for him because you don’t think about them.”

LaRoche said before Friday’s game that the discomfort was trending in the right direction. The latest setback, however, has Williams wondering if he might miss extended time.

“The issue for him is that’s it been a little bit better,” Williams said. “And then he’ll tweak it again and it’s kinda sore. He’s been playing so well and he’s a big part of our offense and defense. We have to look at his long-term health, too, and the long-term health of our club.”