The 7-foot former No. 1 draft pick is good friends with Memphis guard Mike Conley, whom he played with at Ohio State.
Portland waived Oden last March after five injury-plagued seasons with the team. He was recovering from his third microfracture knee surgery when he was let go and had not appeared at the Rose Garden since 2010.
Oden was greeted with mostly cheers -- but a few boos -- when he was shown on the video scoreboard in the first quarter. Oden, seated courtside across the Blazers' bench, offered a peace sign in response.
He didn't want to speak after the game.
"I'm still not doing anything," he said. "I'm here to relax."
Oden was selected over Oklahoma City's Kevin Durant with the top pick in the 2007 draft. The Blazers believed the former Ohio State star could lead the team -- along with Brandon Roy and LaMarcus Aldridge -- to an NBA championship.
But Oden's rookie season was delayed when he had microfracture surgery on his right knee. He had surgery for a fractured kneecap in 2009 then early in 2010 had microfracture surgery on his left knee.
He had another microfracture surgery on his right knee last February.
In all, Oden appeared in just 82 career games for the Blazers, averaging 9.4 points and 7.3 rebounds
His knee problems drew comparisons to Sam Bowie, the injury-plagued center the Blazers took ahead of Michael Jordan in 1984. Bowie played in 76 games as a rookie but appeared in just 63 games over the next four seasons because of injuries.
Oden took this season off to rehab but has had interest from several teams for next season, including the Cleveland Cavaliers. Earlier this month, he went to see the Grizzlies play the Cavs in Ohio.
Mike Conley's father is Oden's agent.
"It was unbelievable to see him," the younger Conley said after the Grizzlies beat the Blazers 94-76. "I had dinner with him last night and I'll probably eat with him tonight, too. Just to see him in good spirits, he's always been a supporter of mine and I've always been a supporter of his.
"I'm just hoping that everything turns around for him and he's ready to go next year."