Chris Fedor of Cleveland.com reported the news, noting the injury is considered "minor" and "nothing of concern." A source told Fedor that Sexton's absence is "absolutely not" related to Thursday's trade deadline.
Sexton, who hadn't missed a regular-season game since he was drafted with the No. 8 pick out of Alabama in 2018, sat out the team's first three preseason games after he twisted his ankle.
The 22-year-old entered his third NBA season off of a sophomore campaign that saw him start all 65 games, with 20.8 points on 47.2 percent shooting from the field while adding 3.1 rebounds and 3.0 assists.
He picked up right where he left off to start the 2020-21 season, averaging 24.0 points with 4.3 assists and 2.8 rebounds through 38 games for Cleveland. He missed five games with a sprained ankle back in January.
At the start of the preseason, head coach J.B. Bickerstaff praised Sexton's growth during his second year in the league.
"I thought he took huge steps, as a teammate, and as a basketball player overall," Bickerstaff said, per Chris Fedor of Cleveland.com. "He was making guys better around him and still able to be effective as a scorer."
Darius Garland, Quinn Cook and Dylan Windler will likely see more playing time until Sexton is ready to return.