Heuer (4-2) was tagged with the loss Saturday against the Marlins after allowing two unearned runs on two hits while fanning one across one inning.
Heuer pitched the eighth with the Cubs holding a one-run lead, but he was unable to maintain that advantage and ultimately gave up both the tying and winning runs -- though both runs came home thanks to a fielding error by Sergio Alcantara. The right-hander, who was acquired by the Cubs from the White Sox before the trade deadline, owns a 2.25 ERA through seven appearances (eight innings) with the Cubs.