Quintana, who's allowed 15 runs over his last seven innings, has been working on getting more extension as he finishes his delivery, Colleen Kane of the Chicago Tribune reports.
White Sox pitching coach Don Cooper has noticed that Quintana is getting up in the zone too much and his fastballs away to right-handers are leaking back over the plate. Cooper added that the left-hander's bullpen sessions have been good, but it's not translating to game action. Quintana will be on the bump Tuesday, when the White Sox open a three-game set on the road against Tampa Bay.