DALLAS -- Dallas Mavericks star Dirk Nowitzki underwent arthroscopic surgery on his bothersome right knee Friday.

The Mavericks announced that Nowitzki, 34, is expected to resume on-court activities within approximately six weeks, which means he will miss the beginning of the regular season.

The Mavs have 13 regular-season games scheduled during that six-week window.

"We've got to really buckle down," Dallas coach Rick Carlisle said. "Six weeks is a long time. A week and a half of it is non-season time, so that's a bit of a plus, but NBA games are hard and we're going to have to have everybody ready to play. Simple as that."

Nowitzki, an 11-time All-Star, has missed the Mavericks' last three preseason games due to swelling and soreness in the knee. He hoped to put off the surgery until after the season, but it was determined that he needed to have the cause of the inflammation dealt with now.

The Mavericks' medical staff drained the knee twice this month, and the swelling returned within days both times. Nowitzki's knee did not respond as hoped to a program of rest, icing and low-impact conditioning work this week, leading to the decision to get the knee scoped.

"If it's going to keep swelling up on me, that's obviously not a way to go throughout an 82-game season and hopefully long playoff run," Nowitzki said Monday after the swelling returned following his participation in three consecutive practices.