Boston Celtics rookie guard Marcus Smart returned to practice Wednesday, but only participated in part of the session, as he works his way back from a left ankle injury.

Smart removed himself from Wednesday's closed practice, according to the team. While it does not appear to be an encouraging sign that Smart will return for Friday's matinee with the Chicago Bulls, the Celtics have another session Thursday before finalizing his status.

Smart suffered a severe sprain and bone bruising after stepping awkwardly on a defender's foot while driving at the basket against the Indiana Pacers on Nov. 7. Despite being stretchered off the court, the team set a return timeline of 2-3 weeks and had recently begun targeting Friday's game, particularly with four days off preceding Chicago's visit.

Celtics coach Brad Stevens has stressed that the team would not rush Smart back to game action and would only reinsert him when he felt comfortable enough to return.

"I think, obviously, you want him to be as close to pre-injury [health] as possible, otherwise he shouldn’t be full-go," Stevens said before Wednesday's practice. "Is there a transition period? Absolutely. But sometimes in those first couple days, you’re so excited to be back out that you actually play pretty darn well. So it’s just a matter of him getting back out here and it’s more about the conditioning than anything else right now, just because he hasn’t done anything on the court, physically, as far as 5-on-5, in the last three weeks."

Celtics guard Avery Bradley, who missed time last season in part due to returning too soon from an ankle injury, said teammates have encouraged Smart to "make sure that your body feels good, listen to your body."

Smart seems to have heeded their veteran advice on Wednesday.

Stevens was asked whether Bradley's setback last season might leave the team leery about bringing Smart back too soon this time around.

"I trust our medical team and medical staff and I think that -- Marcus and Avery I’m sure will share that discussion and talk about that," said Stevens. "We don’t want anybody to come back before they are physically able, because you don’t want to put yourself in a bad spot, or make a lingering [injury] worse and make it linger longer than it otherwise would. I think [Smart has to] talk to others and he’s gotta get their perspective, and he’s gotta put his faith and trust in our medical team. Because they are excellent at what they do."

Stevens said that Smart returning to practice is simply the next step in the player's road back.

"He’s done his rehab diligently and done it well, and he’s stuck to the game plan as far as coming in here multiple times a day and going above and beyond," said Stevens. "So he’s doing what he’s supposed to do and this is the appropriate time frame."

Stevens was asked where the Celtics have missed Smart the most the last seven games.

"I think from the energy-giver standpoint," said Stevens. "And I think he’s got a chance to be a great defender on a given night. And he certainly has a chance to impact the game on the other end on a given night, but it’s more about his presence he has on the floor and I think, certainly, any team could use a guy like that."

Smart has often been lauded for his defense and both the team and individual defensive numbers reflect a positive impact when he's on the court. But Stevens was quick to point out that the Celtics didn't exactly have a glossy record with Smart before he was injured.

"To be real frank, we were 1-3 with him, and losing when he went out, so I don’t want to make it sound like he put all the weight of the world on his shoulders or the burden on his shoulders, because that wasn’t necessarily the case as far as impacting the bottom line, like we’ve talked about in wins and losses," said Stevens. "He helps our defense. He makes us better. His energy makes us better. But we still have to play better to get what we want, even with him in the lineup."

Bradley, who played in successful three-guard lineups alongside Smart and Rajon Rondo early in the year, is excited for Smart's impending return.

"It helps not only me, but it helps our team out," said Bradley. "He brings that intensity on the defensive end and the offensive end. He brings a lot to our team and we’re just excited to have him back on the floor with us."

Added teammate Jeff Green: "The way he can put pressure on guards bringing it up the floor -- he was doing a great job of that before he got hurt and hopefully he can continue to be that effective on the defensive end ... He’s been great for us, and hopefully he’ll continue to play at a high level."