The Nationals designated Mikolas for assignment Wednesday.
Mikolas had been a member of the rotation throughout the season as either a starter or primary pitcher out of the bullpen, but his usage as a mop-up man in relief during Tuesday's 8-6 loss to the Cubs appeared to signal that his time in Washington was nearing an end. The Nationals made it official Wednesday, dropping Mikolas from the 40-man roster to clear a spot for left-hander Jackson Kent, who was called up from Triple-A Rochester to start Wednesday's contest. Mikolas will be available via waivers at a team-friendly $2.25 million salary, but the 37-year-old is unlikely to command much interest after submitting a 5.82 ERA and 1.38 WHIP over his 116 innings with the Nationals.