Jackson allowed four runs on two hits and two walks over one inning in Thursday's loss to the Phillies.
The Atlanta bullpen was mostly a disaster Opening Day -- Shane Carle served up a three-run homer to Maikel Franco in the sixth inning, after which Jackson said "Hold my Gatorade" and surrendered a grand slam to Rhys Hoskins in the seventh. The right-hander was already ticketed for low-leverage work this season, but he could be the first reliever to lose his spot entirely if the front office decides to start churning arms.