Rip Hamilton has a torn plantar fascia in his left foot, the organization announced Sunday evening.
The diagnosis was the result of an MRI the Bulls starting shooting guard had earlier in the day.
The veteran limped off the court and headed to the locker room at the 3:15 mark of Saturday night's Bulls' home win over Philadelphia, then was deemed questionable to return by the team, which initially described the injury as a sprained left foot.
Hamilton, who said afterwards that he heard a "pop," eventually returned to the bench and was reinserted into the contest during the game's final minute for free-throw purposes, knocking down three of four foul shots to help seal the victory over the 76ers.
The 34-year-old, who played in 28 of 66 regular-season games in his debut campaign in Chicago a year ago due to various ailments is averaging 13.9 points per game through the Bulls' first 15 games.
The organization stated that Hamilton "will return to play as his symptoms permit," but if he's forced to miss the Bulls' next game -- Tuesday against Indiana at the United Center -- a person with knowledge of the situation told CSNChicago.com that backup shooting guard Marco Belinelli could start over second-year swingman Jimmy Butler.
Butler has a more prominent role in Bulls head coach Tom Thibodeau's rotation, but his energy and scoring off the bench is considered valuable to the second unit, and he could see the bulk of the minutes on the wing alongside All-Star Luol Deng anyway, the source explained.
The Bulls were plagued with a bout of plantar fasciitis during the 2009-10 season, when Taj Gibson and Joakim Noah, in particular, suffered from the injury, while more recently, former backup point guard C.J. Watson also dealt with the condition.