Uncertainty surrounded the blockbuster trade that sent Kyrie Irving from Cleveland to Boston on Saturday , a day after a physical exam raised concerns about the fitness of former Celtics guard Isaiah Thomas.

The Celtics traded two-time All-Star point guard Thomas, small forward Jae Crowder, center Ante Zizic and the Brooklyn Nets' first-round draft pick in 2018 to the Cavaliers for four-time All-Star Irving on Tuesday.

But multiple US media outlets reported on Saturday that a hip injury suffered by Thomas in last season's playoffs was causing the Cavaliers concern.

Thomas did not have surgery, but Celtics executive Danny Ainge acknowledged that the injury played "some" part in the decision to make the trade, telling reporters that Thomas could miss the start of the season.

ESPN reported Saturday that officials of the teams were to talk on Saturday, and Cleveland could request further compensation from Boston before approving the trade.

Cleveland.com cited two Cavaliers sources on Saturday as saying only that the team was "still in the review process" regarding the trade.

Irving, who reached the finals each of the last three seasons with the Cavaliers, winning the title in 2016, had requested a trade from Cleveland. He was reportedly scheduled to have his physical exam with the Celtics over the weekend.