Walker (6-3) allowed four runs on 10 hits and no walks while striking out five in 6.1 innings to take the loss against the Nationals on Sunday.
Walker had earned wins in each of his last two outings and struck out 21 batters in 14 innings during that time, but he was unable to keep his success going Sunday. He gave up three home runs to Kyle Schwarber prior to his removal, and the right-hander has now posted a 2.42 ERA and 1.05 WHIP in 74.1 innings across 13 starts this year. Walker tentatively lines up to make his next start at home against the Phillies on Saturday.