Dallas forward Caron Butler left the Mavericks' game against Milwaukee in the first quarter Saturday night after injuring his right knee.

The 2.01m forward who entered Saturday's game averaging 15.4 points, grabbed 5 points in the opening nine minutes before being forced to leave the court by the injury and never came back.

The extent of Caron's injury wasn't known after Dallas' 99-87 loss, but the Mavericks were preparing to play an extended time without the 30-year-old veteran.

"We're afraid that it's potentially serious," Dallas coach Rick Carlisle said. "We'll find out (Sunday) where things are at, probably later in the day."

Butler was to stay in Milwaukee overnight and return to Dallas on Sunday to be further examined.