A league source told ESPN.com that Rose also sprained his right ankle during the second half, but that injury isn't believed to be serious, either.
Rose was in good spirits after the game, even joking around with reporters. He said X-rays were negative, but his status for Saturday's game against the Minnesota Timberwolves is uncertain at this point. He had a simple message for the city of Chicago as he got ready to leave the Bulls' locker room.
"Don't worry, it's just an ankle sprain," Rose explained before taking a long-term approach to his health during his brief media session.
"I guess it's part of the process," he said. "Of course the gods are testing me right now, but it's fine. I think I'll be able to get through it."
Rose isn't sure how the initial left ankle sprain occurred, but he wasn't concerned about it after the game.
"It's basketball," Rose said. "It ain't like I tore something, or tore a ligament or something. It's just that I sprained my ankle and I had to sit out. It's minor, and I'll try to give it a go [Saturday]."
Rose scored 18 points in the first half and returned to the game in the third quarter but was largely ineffective, scoring just two points in nine minutes. Rose left the Bulls' bench midway through the fourth quarter and did not return to the game.
Rose finished with 20 points, four rebounds and four assists in 25 minutes of action.
Rose's teammates were glad the injury isn't more serious.
"We hope he's OK," Bulls guard Kirk Hinrich said. "We're going to all say a prayer for him tonight. We got to bounce back [Saturday]."
That's Rose's approach as well.
"Right now I'm feeling good," Rose said. "Of course, my ankle is throbbing a little bit right now but it comes with just playing basketball, and I'm just happy it's not that serious."