DALLAS -- Mark Cuban has a temporary pregame cardio partner.

As Cuban sweated through his normal stair-stepper routine Wednesday evening, Dirk Nowitzki manned an elliptical machine about 10 feet away in the Mavs' weight room.

Nowitzki sat out his third straight preseason game because of his sore, swollen right knee. Guard Rodrigue Beaubois also missed his third consecutive game because of an ankle sprain.

The Mavs' hopes rest largely on Nowitzki's shoulders, but Cuban says he isn't concerned about the 11-time All-Star's knee, although arthroscopic surgery is a possibility if the problems continue.

"Not at all," Cuban said. "He'll be just fine."

Why not?

"Because he's gone through it before," Cuban said. "He went through it earlier in his career with his ankle. Now, his knee, we saw it last year, and we dealt with it. We'll deal with it again this year. That's why we invested in the best medical and training staff in the league."

Cuban, who had been out of town, admitted he hadn't discussed Nowitzki's knee with team doctors or athletic trainers. Cuban figures the worst-case scenario is that Nowitzki would be sidelined for a few weeks if it's decided at some point in the next week that he should have the surgery for the first time in his NBA career.

"I trust our medical staff," Cuban said. "Whatever is going to happen, we're going to be fine."

Unlike Cuban, Nowitzki doesn't grant interviews during cardio work.

"Nah," Nowitzki said. "I'm dying over here."