Damian Lillard will be out for at least six weeks after the Portland Trail Blazers star underwent abdominal surgery.

The point guard had been increasingly troubled by a long-standing injury and decided to take action after playing in a 139-106 thrashing at the hands of the Los Angeles Lakers on New Year’s Eve.

Portland on Thursday confirmed Lillard had been operated on by Dr William C. Meyers at The Vincera Institute in Philadelphia to "repair a core injury causing chronic abdominal pain."

The Trail Blazers are 10th in the Western Conference at 16-24 and must now do without six-time NBA All-Star Lillard for at least a month and a half.

The 31-year-old told Blazers.com: "Last year it was pretty bad.

"Going from that long season, playing a few months without Nurk [Jusuf Nurkic] and without CJ [McCollum] and having to play more minutes, then coming off a short summer after the bubble season where I was hurt in the bubble and going into last year and then not having a break after last year just training for the Olympics, going to the Olympics.

"At the Olympics it was as bad as it'’s been and I was just like 'Man, this is a real issue.' There was really no time for me to do it. I just decided to rest.

"I took like 30 days where I didn't do nothing and I felt a lot better coming into camp. I felt fresh, I had been working out and stuff, it hadn't been giving me any trouble because I was coming off such a long break.

"And then the second that we started camp I felt good the first day, day and a half. Then I started to feel it again and I was like 'Man, I thought the rest would help for a longer period of time.' But it didn't."

Lillard added: "I know [surgery] is ultimately going to be what's best for the team, too. I'd rather be selfish for the team, what I see for our organisation and where I want it to go.

"It makes no sense to keep doing it the way we was doing it. It's like, alright, take a step back to take how many steps forward. It's just what had to happen."

Key man Lillard is averaging 24 points, 4.1 rebounds and 7.3 assists from 29 games this season