Butler was examined by renowned surgeon Dr. James Andrews on Thursday and the Bulls were hopeful he would be able to return to the floor soon.
"Dr. Andrews gave a confirmatory opinion and supports the current management of Butler's condition and return to play. Butler will resume workouts today, be monitored and will return to play when appropriate," the Bulls said in a statement.
Bulls coach Fred Hoiberg echoed those sentiments before Thursday night's game against the San Antonio Spurs. He didn't rule out the possibility of Butler playing in Friday night's game against the Miami Heat.
"He's going to work out tonight and he'll be re-evaluated in the morning," Hoiberg said. "See how tonight went. If everything goes OK, we'll monitor it. I'm sure he'll want to get another good workout in [Friday] and just see how he's feeling. Wouldn't rule [playing Friday] out, but at the same time we're going to be safe with it."
In the game, Butler played 34 minutes, including 21 of the first 24. He practiced the following day and then his knee swelled up and his back stiffened. He also missed Monday's win over the Milwaukee Bucks.
Hoiberg said Butler did not get another MRI during his visit with Dr. Andrews but did acknowledge he might be on a minutes limit when he returns.
"We'll discuss all that in the next couple days," Hoiberg said. "Tonight I think will be a big step in how he's feeling, if that pain has completely subsided and if his back is feeling better. Again, get another workout in tomorrow and then we'll make that determination.''
Hoiberg said that Butler is feeling good about the prognosis.
"I texted with him this afternoon," Hoiberg said. "He's in great spirits. I think he's relieved a little bit after the meeting with Dr. Andrews. And it was exactly what he wanted to hear, and he's excited to get back to the guys.''
Hoiberg acknowledged after Wednesday's practice that it was Butler's idea to see Andrews, an idea the Bulls supported. Hoiberg said the peace of mind Butler will get because of the visit is important.
"I think that's a big part of it," Hoiberg said. "I think the mental aspect is huge in something like this. Jimmy went down and saw one of the best doctors in the world, that's worked on a lot of athletes, and was told that everything looked structurally sound in there. That's I think what he was looking to hear and wanted to hear, now it's about going out there and getting comfortable, and sitting down with Jimmy, putting a plan together on how exactly we're going to move forward with it.''
In other injury news, Hoiberg said rookie Bobby Portis will play after leaving Monday's game because of left orbital injury.