The second makeover of the Dallas Mavericks in as many seasons just got tougher.
Star forward Dirk Nowitzki had arthroscopic surgery on his ailing right knee Friday and the 11-time All-Star isn't expected to resume on-court activities for about six weeks.
Dallas opens the regular season in 11 days at the Los Angeles Lakers.
"It's never going to be easy to lose a game-changer for six weeks," Mavericks coach Rick Carlisle said. "We're going to have to make up for it in other areas."
The 34-year-old Nowitzki has experienced swelling in the knee most of the preseason, twice having the knee drained since training camp started Sept. 29. The knee didn't improve after rest, ice and light conditioning work, leading to the decision to have surgery.
The 2011 NBA Finals MVP played just one preseason game the opener in his native Germany.
The Mavericks already have the challenge of working five new players into the rotation, and one of them can play Nowitzki's position 13-year veteran Elton Brand. Vince Carter, another veteran who joined Dallas last season, also could slide into that spot.
The Mavericks were never much of a threat to defend their 2011 title last season after deciding not to bring back several key contributors. On top of the roster shuffling, Nowitzki had conditioning trouble and a sore right knee early in the season and eventually sat four games. He didn't miss any more time after that.
This is likely to be the most extended absence of Nowitzki's career. He's never missed more than nine games in a season.
"I'm sure you're all not expecting us to be good now, so where is the pressure?" Carter said. "Nobody's giving us a chance with or without him, so for us we've just got to play and let the chips fall where they may."
Nowitzki is the franchise's career leader in points and has averaged 22.9 points and 8.3 rebounds in 14 seasons.
Around the Association
Cavaliers • Cleveland exercised its team option on guard Kyrie Irving, the NBA's reigning Rookie of the Year.
As expected, the team also exercised its third-year option on second-year forward Tristan Thompson, who was taken with the No. 4 overall pick in the 2011 draft, three selections after Irving.
The 20-year-old Irving averaged 18.5 points, 5.4 assists and 3.7 rebounds in 51 games last season. Irving broke his right hand during an offseason practice but is fully recovered. Thompson averaged 8.2 points and 6.5 rebounds in 60 games. The Cavs believe he can score more this season, and average double-digit rebounds.
Cavs general manager Chris Grant said Irving and Thompson "exemplify what we want to be as a team and franchise, both as players and as people."
Nets • Brooklyn exercised its contract option on second-year guard MarShon Brooks, signing him through the 2013-14 season.
Brooks, picked 25th overall by Boston in 2011 and traded to the Nets, averaged 12.6 points and 3.6 rebounds while appearing in 56 games of the abbreviated 66-game season.
He played in the rookie-sophomore game during All-Star weekend and made the NBA's All-Rookie second team.