Jayson Werth returned to the Nationals’ starting lineup Monday. (AP)

Jayson Werth’s shoulder was not 100 percent Sunday night when he returned to action for the first time in a week. The cumbersome-ly named right shoulder joint that kept him out of the Nationals’ lineup from Aug. 10-17 — the acromioclavicular (AC), if you must — still bothers him on his follow-through sometimes. He had to test the shoulder in the cage in Sunday’s late innings to confirm for himself and his manager that he could contribute.

But a walk, a double, two runs and a Sunday night comeback win later, Werth had proven that whatever his percentage of perfect health, it was plenty good enough. Monday, he was back in the starting lineup, batting third and playing right field.

“As far as I know, he’s pretty good today, as evidenced last night,” Williams said. “…I don’t think there will be any issues with it. We’re glad to have him back for sure.”

According to Williams, throwing doesn’t bother Werth’s shoulder, so defense is no cause for concern. The problem comes predominantly on Werth’s follow-through, which inspired the veteran to shorten his swing, he said, in the hopes of relieving the shoulder of some of that strain.

The difference between compensating and adjusting, between bad habits and good tweaks, is small and nuanced. But Williams seems to trust his veteran outfielder is making helpful changes, not harmful ones.

“He may make those adjustments just because he can’t follow through all the way,” Williams said. “It was pretty short last night, good swings to his pull side….that’s a good thing for him if he can make those adjustments on the fly like that and be able to compete.”

Werth was the National League Player of the Month after a monster July in which he hit .337 with 11 doubles and six home runs. He injured the shoulder while making a catch earlier this month, and is hitting .276 with eight walks in 10 August games.