Ja Morant is doubtful for the rest of the 2021-22 NBA playoffs in a huge blow to the Memphis Grizzlies.

The second-seeded Grizzlies were already facing a huge uphill battle to make the Western Conference Finals after falling 3-1 behind to the Golden State Warriors in their semi-final series.

Morant missed the Game 4 defeat to the Warriors due to a knee injury that he and the Grizzlies say was sustained in an incident involving Golden State guard Jordan Poole.

Poole grabbed Morant's knee in Game 3, before the league's Most Improved Player left the court in the fourth quarter of another defeat.

Now, the Grizzlies will likely have to win three consecutive games against the Warriors without Morant – who has a bruised knee bone – in order to advance.

A team statement on Tuesday read: "Memphis Grizzlies guard Ja Morant exited during the fourth quarter of Game 3 of the Western Conference semi-finals on May 7 at Golden State with right knee soreness.

"Morant underwent an MRI, and subsequent evaluation has revealed a bone bruise in his right knee.

"Morant is doubtful for the remainder of the postseason but is expected to make a full recovery."

The Grizzlies performed well in the absence of the former second overall pick during the regular season, going 20-5 during the 25 games he missed.

But Memphis were held to under 100 points (98) for the first time in this postseason in Game 4, with Jaren Jackson's 21 points leading the team.

Morant had been averaging 38.3 points per game in this series, including tying his playoff career high with 47 in Game 2 – the Grizzlies' sole win so far.