Then again, the superstar forward might suit up and play.
Leonard is battling a left knee injury that has bothered him over the past few weeks. Clippers coach Doc Rivers said he doesn't really know if Leonard can play against the Celtics and that he might not have an answer until close to game time.
"Day-to-day," Rivers told reporters of Leonard's availability. "He was very close to playing Monday (against Oklahoma City). It's very possible."
Leonard, the two-time NBA Finals MVP, has been superb when he has played with averages of 26.8 points, 8.9 rebounds, 6.0 assists, 2.1 steals and 1.0 blocks in nine games.
Los Angeles is 7-2 when it has Leonard on the court. Its record without him improved to 2-3 as the Clippers squeaked by Oklahoma City 90-88 on Monday.
Though Leonard's status hovers over the team, Rivers isn't overly concerned. He says he isn't surprised over what is transpiring per Leonard's health.
"We knew at the beginning of the year that this is how it would be," Rivers said. "I don't think one coach or one guy has even thought about it, that it would be nice to have everybody out there."
Smart will undergo further examination but he was optimistic that he could play against the Clippers.
"It was minimal swelling for it. I'm able to walk, I'm able to still shift and plant and move side to side, so that's good," Smart told reporters. "We'd rather be safe than sorry and because it's so early in the season, we don't want to risk anything. We've got a day off, use it to get the treatment I need and be ready for the next game."
Smart, who scored 17 points against the Suns before exiting, said he hurt the same ankle earlier this season. He is averaging 11.8 points and 4.9 assists as one of several key contributors in the team's 11-2 start.
Forward Jayson Tatum led the way with 26 points and a season-best 11 rebounds in Boston's win over the Suns.
The victory was important to the Celtics because they had a 10-game winning streak halted one night earlier by the Sacramento Kings.
"We showed a lot of heart, a lot of fight," Tatum told reporters. "We could have held our heads down after (Sunday). The streak ended and we lost a close game.
"But that's the good thing about the NBA, no matter how good or bad you play, there's another game coming up real soon. That's what matters."
Tatum ranks second on the Celtics with a 20.2 average and leads the squad with a 7.5 rebounding average. The double-double was his second of the season.
Star guard Kemba Walker is the team leader in scoring (23.4) and assists (5.0).
Meanwhile, the Clippers have yet to have Leonard and star forward Paul George on the court together.
George has returned from offseason surgery on both shoulders to average 29.3 points over his first three games.
He scored 33 points against the New Orleans Pelicans in his team debut on Thursday and added 37 two nights later against the Atlanta Hawks.
He only scored 18 points in 29 minutes against the Thunder -- his former team -- but he hit a go-ahead 3-pointer with 25.9 seconds left to help Los Angeles improve to 8-1 at home.
George relished the winning shot as he has heard the scuttlebutt that he's not the guy to look for if a clutch basket is needed.
"You know, there was a big thing about (how I) can't make it to win games," George said. "That stuff doesn't bother me. I am out there to play hard and to win games. I feel confident in every shot that I take. It's up to me to make it or miss it. That type of stuff don't bother me."
The Clippers have won three straight meetings and nine of the last 12 vs. Boston. Last season, Los Angeles averaged 131.5 points while winning both matchups.
--Field Level Media