Dallas Mavericks center Chris Kaman passed the NBA-mandated cognitive testing for players who suffer concussions, according to two sources, but persistent headaches have prevented him from being cleared to practice or play. Kaman recently referred to the cognitive testing, part of the NBA's concussion protocol instituted before last season, as "the stupidest test ever." "For so many years in the NBA, they never had to do that stuff, and now they come up with all that concussion protocol crap," Kaman said before passing the test last week. "It's not cool, but it is cool, I guess. It keeps people safe." The 7-foot Kaman has missed seven games since sustaining the concussion when he banged his head on the court during the Mavs' Jan. 28 practice. Coach Rick Carlisle has said he will not provide any updates on Kaman's condition until the center is cleared to practice. The league's concussion protocol requires players to go through a multi-step process to be cleared to return to practice and games. That includes the passing of cognitive testing, resolution of symptoms and physician clearance. Kaman's role once he returns is uncertain. He lost his starting job the week before he was injured and played 12 and 11 minutes in his past two games, which prompted him to express frustration with his reduced playing time.