According to Joe Vardon of The Athletic, the source said Irving is "OK" but didn't provide a potential timeline for his return.
When asked why Kyrie missed Thursday's game, Nets head coach Steve Nash said: "I can't really comment because I haven't spoken to him and it's personal reasons."
Nash added the following on Friday night prior to the Nets' game in Memphis:
Along with Kyrie, the Nets were without Kevin Durant and Tyler Johnson because of potential exposure to COVID-19, although neither has tested positive to this point. Nash said KD could be back for Sunday's game against the Oklahoma City Thunder if he continues to test negative.
Even without their top two players in Irving and Durant, the Nets prevailed 122-109 on Thursday against a Sixers team that entered the game with an NBA-best record of 7-1. Caris LeVert was the driving force behind Brooklyn's win, finishing with 22 points, 10 assists and seven rebounds. Joe Harris added 28 points off the bench as well.
Although Nash had not spoken to Irving as of Thursday, Andrews noted that Kyrie was in contact with "several members" of the Nets organization.
While Irving has missed two of the Nets' nine games this season and KD has missed three, they have been a force when on the court both separately and together.
Durant leads the team with 28.2 points per game to go along with 7.0 rebounds and 4.8 assists, while Kyrie is averaging 27.1 points, 6.1 assists and 5.3 rebounds per contest.
This is Irving's second season in Brooklyn, but he was limited to just 20 games last season because of a right shoulder injury, while Durant missed the entire 2019-20 season during his recovery from a torn Achilles.
The Nets are 5-4 this season, but they have shown the potential to be dominant and a championship-contending team when Irving and Durant play. Brooklyn figures to be a force to be reckoned with again when Kyrie and KD next reunite on the court.