Stanton tweaked his injured right calf while running the bases this week, and he may now need more imaging, Bryan Hoch of MLB.com reports.
Stanton had been ramping up toward a return to action, and manager Aaron Boone suggested Saturday that the slugger had been expected to be activated during the early portion of the Yankees' upcoming homestand, which begins Tuesday. That plan is now in peril, though it's unclear at this point how much Stanton's setback this week will push back his timeline. If the veteran needs additional imaging, the results of those tests would likely provide insight into how much more time he'll need to miss.