The good news for the Dallas Mavericks is that Shawn Marion seemed to walk away from examinations and treatment today on his sore left knee in a pretty good mood.

"Just finished a great few hours of treatment," Marion tweeted around 2 p.m.

The bad news is the 6-foot-7 small forward remains in Dallas where, according to what coach Rick Carlisle told reporters at the team's shootaround in Denver, Marion was to have his left knee "thoroughly" examined today. Tonight will be the second consecutive game Marion will miss because of a knee situation that he has played through for weeks.

It is now becoming a concern to Carlisle.

"When you’ve a guy that’s played every game and then he misses two games, it’s a concern,’’ Carlisle said. "We care about him a lot because he’s one of our main guys and he’s really been one of our warriors all year long. We’ve got to get to the bottom of it and hopefully we can get him back quickly because we need him. Defensively, he’s the best we’ve got."

Defensively, Marion has been tasked with guarding up to three positions in any one game. He's been a life saver during the past month with guard Delonte West shelved with a broken right finger. The Mavs' elder backcourt of Jason Kidd and Vince Carter simply can't keep up with many of the young and quick point guards they face most nights and Marion has led the charge against them.

His absence now puts Rodrigue Beaubois on the hot seat to come through with high-intensity play at both ends of the floor.

Tonight, Beaubois, working on four consecutive strong outings, will surely get plenty of time matched against Denver's Ty Lawson. On Wednesday, new Lakers guard Ramon Sessions will be a challenge and Friday, a well-rested Tony Parker will give Beaubois another test.

Of course, the Mavs are hoping that Marion, 33, is back in the lineup for the Lakers game to take on Kobe Bryant and that the soreness in his left knee will simply fade away.