"I didn't cut one loose, I can tell you that," Robertson said. "I'm still trying to just take it slow."
Robertson suffered a bone bruise on his right foot on Wednesday evening, when the right-hander missed a step going down the stairs of his spring residence while taking out cardboard boxes for recycling.
"These next three or four days out of the boot are probably pretty important, how his foot responds as we increase activity," Yankees manager Joe Girardi said.
Robertson is continuing to receive treatment and can expect some amount of building back up to game shape, but it is not thought to be enough to place his beginning of the season in jeopardy.
"I think I'll easily be ready for Opening Day," Robertson said. "As long as I have no setbacks, I don't see why I wouldn't [be]. As long as I can play catch a few times, get back on the mound and get a few outings in the games, I'll be set."