Coulombe was optioned back down to Triple-A Nashville on Saturday.
Coulombe served as the club's 26th man during Game 2 of Friday's doubleheader and narrowly escaped a jam after allowing three hits. The left-hander will likely return to Oakland in the near future once the bullpen needs some replenishments, as he's been relatively sharp over his last 15 appearances, logging a 2.13 ERA and 1.34 WHIP dating back to May 5. In a corresponding move, Nick Martini was recalled from the minors.