Iglesias (7-5) got the loss in Sunday's 3-2 defeat at the hands of the Athletics, allowing an unearned run on a hit and a walk.
Iglesias was brought in to pitch the top of the 10th and permitted placed runner Matt Olson to score after surrendering two more baserunners. The loss is the first negative mark on Iglesias' ledger since late July, and he still has a low 1.80 ERA across five innings this month.