Griffin hasn't played a regular-season game for the Clippers after injuring his kneecap in their final exhibition Oct. 23, wincing in pain as he landed after a dunk. After resting the stress fracture for weeks, the former Oklahoma star recently increased his workload, running on an anti-gravity treadmill.
He developed pain in his knee, and an examination Tuesday revealed his recovery wasn't progressing properly. He's the second top selection in the last three years to miss his entire first season with an injury. The Blazers' Greg Oden, chosen No. 1 by the Blazers in 2007, had microfracture surgery on his right knee three months after the draft. Last month, Oden also broke his left kneecap and was lost for the rest of this season.
Griffin, a power forward, averaged 13.7 points and 8.1 rebounds during the preseason.