Swarmer was designated for assignment by the Cubs on Saturday, Tim Stebbins of NBC Sports Chicago reports.
Swarmer was optioned to Triple-A Iowa on Wednesday and will lose his spot on the 40-man roster as part of a move after Steven Brault's contract was selected Saturday. Swarmer has logged a 2.08 ERA and 0.95 WHIP in 39 innings over nine appearances (five starts) in the minors this year and will likely remain in Iowa if he goes unclaimed on waivers.