Leon Powe knows what lies ahead – a third reconstructive surgery on his left knee after tearing his anterior cruciate ligament in Monday night’s NBA playoff game.

On Wednesday morning, the former Cal and Oakland Tech High star was trying to cope with another challenge – Leon III, his high-energy, 15-month-old son. “He’s running around, driving me crazy,” Powe said by phone from his home in the Boston area. “I can’t catch him.”

Powe, in his third season with the Boston Celtics, won’t be moving quickly anytime soon. He’s awaiting a report on Thursday or Friday from the Steadman Hawkins Clinic in Vail, Colo., where results of tests on his knee were sent. A surgical plan will be developed from there.

Bernard Ward, Powe’s longtime friend and mentor, drove the 6-foot-8 forward to the hospital in Boston on Monday night and spent Tuesday with him before returning to the Bay Area. “He’s a little down right now, but it’s gotten better each day,” Ward said of Powe’s mood. “He knows it’s an uphill battle, but he’ll be all right.”

Powe, 25, has been through this twice before, most recently after his freshman season at Cal in 2004. He had reconstructive surgery for the ACL injury at the Steadman Hawkins Clinic.

Rehabilitation time for ACL surgery typically is 9-to-12 months. Powe said he doesn’t know yet just how much of next season he could miss. After surgery in the spring of 2004, he sat out the entire 2004-05 season at Cal before returning to play in 2005-06.

Powe has been tested throughout his life. Without a father since birth, Powe and his family moved from place to place in the East Bay during his childhood, dogged by poverty and his mother’s struggles with drugs.

His mother died when he was at Oakland Tech, which he twice led to the state championship game. An at-risk student early in high school, Powe improved his academics and he earned a basketball scholarship to Cal, where he became the Pac-10 leading scorer and rebounder in 2005-06.

Powe, who averaged 7.7 points and 4.9 rebounds this season, becomes a free agent after this season. He believes the Celtics will continue to have faith in him.

“They know I’m about hard work,” he said.