DALLAS -- The Mavericks remain tight-lipped about Dirk Nowitzki's rehab process, but there are at least some rumblings about progress.

Nowitzki underwent arthroscopic surgery on his right knee a month ago, an operation that typically has a recovery timetable of three to six weeks.

"He's picked up his activity level, but I'm not going to get into exactly what he's doing because it's not my place," coach Rick Carlisle said.

Added owner Mark Cuban: "I see him working harder and harder on all the (exercise) machinery, so that's a good sign. ... You can tell he's picked up the intensity."

The 34-year-old Nowitzki did a few leg presses in the team's weight room under the supervision of athletic trainer Casey Smith during the open access period, when the media was talking to Cuban at a nearby elliptical machine. Nowitzki, who had already worked up a sweat, smiled and waved when asked if he wanted to chat.

Nowitzki hasn't addressed the media since a few days after the operation other than an appearance on the team's television broadcast, when he expressed frustration that his recovery hadn't been as quick as he hoped and anticipated. Nowitzki intends to take questions from the media "soon," according to a Mavs spokesperson.