Kerr told reporters that Looney is undergoing further evaluation and receiving a second opinion of the non-displaced first costal cartilage fracture he suffered in Game 2.
Additional tests will decide Looney's next moves and whether he is able to return to the NBA championship series.
"We're gathering information. Second opinion type thing," Kerr said Thursday. "So it's sort of open, it's an open question as we gather information. At this point, there's not really anything to report. We are looking at all of our options and his options."
The Warriors officially listed Looney as questionable on the league's injury report Thursday night. It was initially expected that the center's injury, which resulted from a hard fall after making contact with Toronto Raptors forward Kawhi Leonard, would keep him out for the rest of the series.
Kerr previously told reporters Tuesday that Looney was out for the Finals.
"It's not anything that's going to be a problem long term," Kerr said. "But it's going to keep him out for the rest of the series, which is obviously a big blow for us and for him. He's had such a great season, such a great postseason run. Fortunately it won't affect his future, but it's a big loss for us."
Along with Looney, the Warriors played without guard Klay Thompson and forward Kevin Durant in Game 3 Wednesday night. Thompson sat with a left hamstring strain and Durant, who hasn't played since Game 5 of the Western Conference semifinals against the Houston Rockets, remained sidelined with a right calf strain.
Thompson is expected to play in Game 4, but Durant has already been ruled out. Game 4 is Friday night at Oracle Arena in Oakland, Calif.