CHICAGO -- Rajon Rondo was out of his cast Monday but won't play in Game 5 Wednesday against the Boston Celtics, while Isaiah Canaan gets the start at point guard, Bulls coach Fred Hoiberg said.

Canaan made a surprise appearance in the Bulls' Game 4 loss to the Celtics on Sunday night, scoring 13 points in 34 minutes.

The Bulls' point guard situation has been in flux since Rondo suffered a fractured right thumb in Game 2. Rondo initially said he'd be out at least "a couple weeks" after being placed in a hard cast for the thumb injury, and a wrist injury he has been dealing with over the last few weeks.

Though he wasn't wearing the cast Monday, Hoiberg ruled Rondo out of Game 5 but left the door open for a potential return in Game 6 or a possible Game 7.

Rajon Rondo is relegated to the bench for Game 5 but could return in the series. AP Photo/Charles Rex Arbogast

"His wrist tendon has quieted down a little bit," Hoiberg said before Monday's practice. "So just decided to remove the cast. He's still in a splint for his thumb."

After winning the first two games of the series with Rondo, the Bulls have regressed badly without him on the floor, losing the past two games to the Celtics. The offense no longer has pace and has been unable to function with the combination of Jerian Grant, who started both games in Rondo's absence, and Michael Carter-Williams. The pair have combined to shoot 6-for-28 in the series and have turned the ball over nine times in the last two games.

Hoiberg's desperation is so great that Canaan will make his first start of the season in the fifth game of the playoffs. Canaan wasn't even active for Game 3 and is now being thrust onto the playoff stage.

If the Bulls are going to find a way to win another game in this series, the point guard issue is just the largest of many worries. Hoiberg also must figure out how to get veteran guard Dwyane Wade more involved in the offense. Wade scored just 11 points over 38 minutes in Game 4.

"I was just talking to Coach about that," Wade said. "Obviously with Rondo going down, the ball's going to be a lot more in my hands. But I talked to coach about it, there were a couple opportunities where I could have been more aggressive. Some of it is on me. Sometimes when I'm running the offense, I'm doing it. I'm passive. I come off and the first screen is a pick-and-roll, I get off of it, and it doesn't come back. So I have to figure out a way to, certain times be more aggressive than I was last game. And I'll figure it out. I've been playing a long time, so I'll leave it up to myself to figure it out."

Wade believes that the Celtics' decision to play a smaller lineup has changed the series. Aside from getting Rondo back, Wade knows the Bulls have to make some adjustments of their own heading into Game 5.

"It changed it entirely," Wade said of Boston's decision to play more small ball. "Obviously when it was big-big, we dominated them -- dominated them defensively. Our defense was incredible. They made adjustments. We didn't need to because we were up 2-0. Then coming off of Game 3, we felt watching the film we played [with a] low motor, not enough energy so we didn't feel the game plan was necessarily the key. But it was coming out of Game 4. So now I'm sure it will be a few adjustments we'll look to make, and hopefully it makes a difference."