Then, they lost to the Boston Celtics.
The Bulls announced Rondo was out indefinitely hours before they dropped Game 3 on Friday, tightening their first-round series after Chicago took the first two at Boston. Rondo's injury in Game 2 is a big blow for a team trying to become the sixth No. 8 seed to knock off a No. 1.
''Rondo obviously has been unbelievable in the two wins we had in Boston,'' coach Fred Hoiberg said. ''So to get the news we got last night obviously was very difficult.''
X-rays confirmed the fracture, and surgery is not required. Hoiberg said Rondo - also playing through a right wrist injury - will probably be re-evaluated in a week to 10 days.
Hoiberg said Rondo was injured swiping for the ball in the third quarter of Game 2. He either hit the ball or Boston center Kelly Olynyk's elbow, but stayed in the game.
Rondo was able to run in practice on Thursday but did not have any contact. Picking up the ball was painful.
Rondo said he can't even hold a fork with his thumb, and he wasn't about to predict when he will return.
''It depends on what I can tolerate,'' he said. ''I'll check in every two days, see if I can pick up a ball. But right now, I can't even use a fork with my thumb. It's going to take a couple days to see how I feel. Hopefully things get better.''
Hoiberg said it's ''too early to tell'' if Rondo would play in the second round should the Bulls advance. Without him, Jerian Grant starts with Michael Carter-Williams backing him up. Jimmy Butler and Dwyane Wade also figure to run the offense at times.
''It's tough when any of your soldiers go down, man,'' Butler said. ''Especially someone who wants to win as bad as he does, that studies the game and wants to do well by everybody like he does. It's definitely a loss for all of us. But damn. I mean, we wish we had him, but we don't. There's not too much more to say about it.''
Rondo played well in Game 1 and was particularly good in Game 2, just missing a triple-double with 11 points, 14 assists and nine rebounds as the Bulls put Boston in an 0-2 hole. Just as important was his defense on Celtics star Isaiah Thomas, which took some of the load off Butler.
''It's a totally different team,'' Boston's Jae Crowder said after Friday's game. ''We felt like with the switching we were throwing a curveball at them. We tried to make them as stagnant as possible without the primary ball-handler, which is Rondo - passing the ball and creating for others. We had a good game plan going into it.''
The injury comes at the end of an up-and-down first season in Chicago for Rondo. A four-time All-Star who won an NBA championship with Boston in 2008, he was at the center of a major flare-up in January. He fired back at Butler and Wade while defending the team's younger players after the two stars criticized the team following a loss, resulting in fines for the veterans.
Rondo also got suspended for a game by the team earlier in the year and was in and out of the rotation. The Bulls sat him for five straight games at one point, but he started down the regular-season stretch and played well.
''Rajon's experience in these types of settings is invaluable,'' Hoiberg said. ''To miss that now with him being out, most likely for the rest of the series, it does put some extra responsibility on some guys. Again, we've been through this. We had other guys that have had to step up in players' absences.''
More AP NBA: apnews.com/tag/NBAbasketball