With 8:08 left in the third quarter, after getting called for a foul against Memphis forward Zach Randolph, Nowitzki's frustration with his rusty play spilled over. He took two quick technicals from official Eric Dalen and was ejected, finishing with seven points and five rebounds in 15 minutes.
"I guess I didn't think it was a foul," Nowitzki said. "We talked about it, and I got tossed."
Nowitzki missed the past nine games with a sprained right knee suffered Dec. 27 against Oklahoma City and watched the Mavericks drop seven of those, including the past four.
Meanwhile, the Mavericks were without starting center Tyson Chandler, who was back at the team hotel fighting an illness. He's been sick since Thursday and gutted out 16 minutes Friday night in a 101-89 loss at San Antonio.
Brendan Haywood started at center.
Nowitzki's shots were falling as he warmed up before the game, though he seemed a bit tentative in moving on the court at first.
Mavs coach Rick Carlisle said before the game that he would closely monitor Nowitzki, who wore a sleeve over his right knee for additional stability, and had an idea of how many minutes he'd like to play his leading scorer, although he would not divulge his plan.
"It's been a difficult, challenging stretch, but I think the reality is this begins another process," Carlisle said. "We're all going to be sensitive to the fact that he's been working on his own to get back and he and [head athletic trainer Casey Smith] have been working very closely on his rehab and his conditioning. He hasn't had a real practice.
"Tonight is going to be right back into an NBA game. I think we all just need to be aware that that is a challenging situation."
Jeff Caplan covers the Mavericks for ESPNDallas.com. Information from The Associated Press was used in this report.