Clippard was designated for assignment by the Nationals on Tuesday, Jesse Dougherty of The Washington Post reports.
Clippard was activated from the 15-day injured list Aug. 12 and surrendered four runs with a 3:4 K:BB and four hit batsmen over three innings before Washington opted to move on. The veteran right-hander posted a 2.23 ERA, 1.20 WHIP and 53:18 K:BB in 36 appearances for Triple-A Rochester before being promoted, and it remains to be seen if he elects to return there or hit free agency, assuming he passes through waivers unclaimed.