Celtics coach Brad Stevens told reporters at the team's morning shootaround that Irving experienced soreness throughout Saturday's loss in Houston and woke up sore on Monday.
"[Irving] was experiencing some discomfort, some soreness [during the Houston game]," Stevens said. "Woke up [Sunday] and felt a little bit better; woke up today and did not feel any better. So, obviously, with that left knee we're going to make sure that we do right by Kyrie, first and foremost, and make sure he feels great."
Stevens said Irving did not have to get an MRI on his sore knee, but acknowledged his star guard might have to miss another couple games.
"It doesn't sound like it's a long-term concern," Stevens said. "But it certainly could last through the week."
Irving echoed Stevens, and indicated the precautionary rest was more about maintenance.
"It's been about two years coming off knee surgery, so you have to do things like that, stay on top of it and make sure you're doing the right things," he said. "Sometimes it may be a little bit extra just from the demand you put on your body and then also the realization of how much basketball you've actually been playing for the last few years.
"The level in which you demand your body to play at -- it's part of the game and I think that's the luxury of being in the regular season and having times where you can kind of put yourself first and just take care of yourself and then go from there."
Monday marked the eighth game Irving has missed this season, but the team didn't seem to miss him in a 105-89 rout of the Bulls. Boston is now 6-2 without him, though one of those losses came during the Celtics' other visit to Chicago in December, when they were thumped, 108-85.
Irving had been spectacular since the All-Star break but was held to 18 points on 6-of-17 shooting during Saturday's loss to the Rockets.
Stevens told reporters he was uncertain whether Irving would be available Thursday when the Celtics wrap up a three-game road trip by visiting the Minnesota Timberwolves.
"I just want to make sure I'm as healthy as possible," Irving said. "It's just at this point in the season it's just about the big picture, so I'm just trying to stay smart and get out of my own way and when it feels good get back out there."
Irving is averaging 24.8 points, 5.1 assists and 3.7 rebounds over 32.5 minutes per game this season. The Celtics (44-20) sit two games behind the East-leading Toronto Raptors (45-17) entering Monday.
Shane Larkin started in place of Irving, as Stevens said he didn't want to disrupt the rhythm of the second unit.
"The bench is playing so good," Stevens said. "I don't want to mess with that. Obviously, we'll do it game by game, matchup to matchup if Kyrie misses more games, but we want to keep that bench group together as much as possible."
ESPN's Nick Friedell contributed to this report.