(AP Photo/David J. Phillip)

First baseman Adam LaRoche, the Nationals’ best hitter through the season’s first month, is resting a sore quadriceps and expects to return the Nationals’ lineup Friday in Philadelphia.

LaRoche first hurt his quad last week, when a groundball struck him in the muscle. It felt gradually worse during Tuesday’s 4-3 victory, in which LaRoche hit the game-tying double and game-winning single. It hurt him especially bad running to second on the double, Manager Matt Williams said.

“It kind of dies down a couple days, and then it will flare up,” LaRoche said. “It was really hurting yesterday. It’s part of it. It’s part of getting old.”

LaRoche will be available off the bench as a pinch hitter, Williams said. LaRoche leads the Nationals in most offensive categories, hitting .312/.413/.495 with four home runs and 17 RBI.

“I thought, I don’t want to take him out of the lineup, but it’s probably better to give him two” days, Williams said. “We’ve got subsequent off days coming, too. We’ll try to get him as much rest as we can, try to calm it down. He’s been dealing with it. It’s a little bit worse today than it has been.”

With the Nationals already short middle-of-the-order hitters Ryan Zimmerman, Bryce Harper and Wilson Ramos, it hurt Williams to give LaRoche the day off. But he said he felt confident in Tyler Moore against a left-handed starter, and he wanted to ensure LaRoche does not join those hitters on the disabled list.

“It’s long-term thought,” Williams said. “Over the course of the season, we’re going to need him. I don’t want to get him in a situation where he’s going to be out for an extended period now. I’d rather take a day, make sure he’s good, give him the off day tomorrow and see where we’re at. I don’t want to take him out, for sure.”