"We're still working through it," Kingsbury said.
There's a chance that the injury could land Butler on injured reserve, but Kingsbury said it's too early in the process to decide.
"If that's the direction it has to go, then obviously, that's unfortunate," Kingsbury said. "We wouldn't be able to develop him like we wanted."
Butler was the first pick of the fourth round out of Iowa State.
Butler played 22 snaps in Thursday night's preseason game against the Oakland Raiders and finished without a catch on one target.
If the Cardinals lose Butler for any significant amount of time, it'll be a blow to the size of the unit.
"I think just when you have his height, size, speed, that's an element that you want on your roster," Kingsbury said. "Unfortunately, if he's not available, it's hard to find 6-5 guys, 6-6 guys who are running sub-4.5. But other guys have stepped up."