Per ESPN.com's Tim Bontemps, "Virtually everyone involved with the Celtics has been some combination of disappointed and frustrated," both with the team's overall play and "especially" with Irving.
Irving has increasingly been using the media to air out grievances with his teammates. He told reporters after a Dec. 21 loss to the Milwaukee Bucks that the Celtics weren't playing with a team-first mindset.
"There's obviously some selfish play going on out there," Irving said. "I get caught up in that as well. I literally can do anything I want out there at any time I want. But at the same time, it's what can I do for my teammates to be more successful?"
Per The Athletic's Shams Charania, Irving had a "heated moment" with head coach Brad Stevens on the Celtics bench during a Nov. 24 loss to the Dallas Mavericks.
After previously saying he intended to re-sign with the Celtics this summer, Irving changed his tune Friday by telling reporters to "ask me July 1" what his plans are.
Despite Irving's frustration, the Celtics are still in prime position to make a run at the NBA Finals this season. Their 33-19 record is good for fourth in the Eastern Conference, and they're five games behind the top-seeded Milwaukee Bucks.
Irving is leading the team with averages of 23.6 points and 6.9 assists per game.