Damian Lillard has been ruled out of the NBA All-Star Game after suffering a groin injury in the Portland Trail Blazers' defeat to the Memphis Grizzlies.

The 29-year-old was due to be part of Team LeBron, yet the five-time All-Star will instead take a watching brief on Sunday night - insisting he will be at the game in Chicago, but as a spectator.

Lillard announced his unavailability after scoring 20 points for Portland in their 111-104 setback against the Grizzlies.

He said: "That's something you look forward to, those festivities and having fun. But my health is first, and I knew right away. I'll still be there and be a part of it, but I'm not going to play."

His injury occurred in the fourth quarter, in an awkward landing.

"When it happened, I just felt it," said Lillard.

"I knew I pulled it, it made no sense to be out there for the last few minutes of the game and risk trying to play through it and making it worse.

"But I walked off the court just fine even though it was like, a little bit painful. I came in and it was strong when they were making me go against resistance and stuff like that.

"It was strong, wasn't like, weak and I couldn't do stuff. That was all I needed to know."

Lillard said he hoped his place would go to a worthy substitute, naming the Phoenix Suns' Devin Booker as a possible candidate.

He is set for an MRI scan on Thursday to determine the seriousness of the injury, which also rules him out of the three-point contest in the All-Star break.

It remains to be seen whether he is available for the Blazers' next outing, a February 21 home game against the New Orleans Pelicans.