The Mavericks announced that Nowitzki, 34, is expected to resume on-court activities within approximately six weeks, which means it's certain that he will miss the beginning of the regular season.
The Mavs have 13 regular-season games scheduled during that six-week window.
Nowitzki wrote on his Twitter account (@swish41 ) Saturday, "Thanks for all the kind words and thoughts and prayers. Means a lot to me. I hope to be back out there pretty soon. Will keep u posted."
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 again following his participation in three consecutive practices.