The Nationals designated Collins for assignment Wednesday, Jamal Collier of MLB.com reports.
Collins was removed from the active and 40-man roster to clear a spot for Matt Adams (finger), who was activated from the 10-day disabled list following a three-week absence. The lefty reliever accrued a 2.77 ERA, 1.54 WHIP and 8:6 K:BB over 13 innings across 17 appearances -- his first in the big leagues since 2014. Collins is expected to report to Triple-A Syracuse if the Nationals are unable to find a trade partner for him and if he goes unclaimed off waivers.