Dunleavy was expected to return to action in December after missing the start of the season due to a back operation he required before training camp.
However, the 35-year-old could be facing a longer stretch on the sidelines if it is confirmed that more damage has been done during his recovery.
"Mike is going to see a doctor again and then we should have a better update after that," Hoiberg told reporters. "He had a little bit of soreness. But we'll have more on that."
The Bulls, who currently hold a 9-5 record this season, host the San Antonio Spurs on Monday night.