The chances of Kyrie Irving returning to the Celtics seems to be more and more unlikely as free agency nears. 

According to The Athletic, which cited unidentified league sources, the six-time All-Star will not opt into his $21.3 million deal for next season and will instead become a free agent. He will be eligible to sign a new contract either with Boston or another team. The report adds that the Celtics were expecting this move ahead of his option date.

Irving's future with the Celtics has become highly speculated after the guard's second season in Boston, and there have been rumors that Irving could land with the Nets, Lakers or Knicks in free agency. 

Boston acquired Irving in a blockbuster trade with the Cavaliers in August 2017. He carried his team to the Eastern Conference semifinals during 2018-19 after the Celtics finished the regular season with a 49-33 record. 

Celtics president of basketball operations Danny Ainge said earlier this month that no matter what happens with Irving in free agency, he doesn't regret making the decision to trade for Irving.

“There’s always risk in making deals. We’re not afraid of risks,” Ainge said (per bostonherald.com). “We made a risk by trading for Kyrie. And no matter what happens with Kyrie, I'll never regret that. Just move on to the next deal.”

The Celtics entered the season as favorites in the East, but Boston fell out of the playoffs after losing to the Bucks 4-1 in its semifinals series.

“The whole Kyrie thing, it’s unfortunate that one person gets credit or blame for a team’s failures,” Ainge said. “We had a lot of reasons why the team didn’t succeed this year. And Kyrie deserves his share of the blame but not any more than anybody else. There’s a lot of guys that didn’t handle things the right way.”

Irving, who previously spent six seasons with Cleveland, averaged 23.8 points and 6.9 assists for Boston this season.

NBA free agency starts June 30 at 6 p.m. ET.