Brooklyn Nets head coach Steve Nash said the NBA title hopefuls are waiting to discover the severity of Kevin Durant's latest injury after the superstar was ruled out early in the loss to the Miami Heat.

The Nets endured a forgettable trip to Miami, suffering a buzzer-beating 109-107 defeat against the Heat, having seen Durant exit in the opening quarter due to a left thigh contusion on Sunday.

Durant missed 23 games because of a hamstring injury before returning this month and the Nets – eyeing their maiden championship – are hoping they are not without the former MVP for another sustained period.

"He's sore but we don't know how severe," first-year coach Nash told reporters post-game.

"We'll see tomorrow how he wakes up and go from there but right now nothing’s been determined."

Durant was hurt during the first quarter, appearing to tangle legs with Trevor Ariza on a drive to the basket during the first quarter.

The 11-time All-Star had played for just four minutes, going three-for-three shooting – including two successful attempts from beyond the arc – to finish with eight points.

Durant was out for nearly two months of the season due to a hamstring injury, making his return against the New Orleans Pelicans on April 7 with 17 points in just under 19 minutes.

The two-time NBA champion did not dress for the defeat to the Philadelphia 76ers (39-17) on Thursday, a result that means they hold the tie-breaker over the Nets (38-19) in the Eastern Conference, but was back in action on Saturday, scoring 25 in the victory over the Charlotte Hornets.

"The timing of everything this year has just been a tell-tale sign of what life is right now in terms of the uncertainty of a lot going on," said Nets star Kyrie Irving, who posted 20 points in the continued absence of superstar James Harden (hamstring).

"Anything could happen at any moment, so we don't want to take anything for granted. But anytime one of our team-mates goes down, anytime something like that happens, it's definitely going to take a hit for us. And he's just gotten back. We just pray that it's not too serious and he's able to recover, but it definitely has a hit on our continuity at times. But we're not making any excuses for each other.

"We're all professionals, the guys that are getting minutes right now, we need them. So it's going to turn eventually, but we've just got to find that continuity, that connectivity from the start of the game to the end."