EL SEGUNDO, Calif. — Metta World Peace and Thomas Robinson both went into training camp with only a small chance of making the Los Angeles Lakers' roster.

They seized that chance and wouldn't let it go, much to the surprise of coach Luke Walton and general manager Mitch Kupchak.

The Lakers kept the two veteran forwards on their opening night roster Monday, waiving Chinese 7-footer Yi Jianlian and forward Anthony Brown.

Yi requested his release after realizing he wouldn't have a prominent role immediately with the Lakers. Brown, a second-round pick last year, simply was outplayed by the 36-year-old World Peace and Robinson, who is with his sixth team in five NBA seasons.

"As much as I like (Brown), and as well as he was playing, Metta World Peace and T-Rob, they were bringing it every single day," Walton said after practice. "They were giving us a toughness that I think we need, and giving us some vocal leadership, some experience, and I just felt like in talking with the guys upstairs, that was what was most valuable for those last couple of spots."

When the Lakers return from the worst season in franchise history against Houston on Wednesday, they'll do it with World Peace on their roster for the second straight season after his NBA career appeared over. Kupchak acknowledges he didn't expect World Peace to make the team again this year, but the former Ron Artest continues to provide veteran stability and defensive ability.

World Peace begins his 17th NBA season this week, and he credits his longevity to a personal reawakening in his mid-30s. After living a "very reckless" lifestyle, World Peace embraced a healthy existence and gained a cerebral understanding of his role with the Lakers.

"It's weird — at the end of my career, I feel like the beginning," said World Peace, who turns 37 next month. "I've got a goal, a personal goal, of trying to reach 20 years, and in order to reach those goals, I've got to take care of my body, have that body freedom. I have to have a no-partying lifestyle, eating the right ways. Obviously there's such a thing called Father Time, but if you take care of your body, you'll have a chance to run with these young guys. These boys are fast, they're jumping all over, and in order to compete, you've got to treat your body the right way."

World Peace was out of the league for 18 months between his release by the New York Knicks in early 2014 to his return to the Lakers, playing in China and Italy during his absence.

Yi returned to the NBA last month after a four-year absence, agreeing to an incentive-laden contract with the Lakers. The 7-footer was the sixth overall pick in the 2007 draft before returning to China in 2012, becoming his domestic league's dominant player.

Yi averaged 3.0 points and 2.5 rebounds during the preseason.

"I think he wanted a bigger role, bigger minutes than we had available," Walton said. "He was really going to have to outplay everybody to get big minutes because of the players we need to develop, and he did a great job. He was great while he was here. He proved that he belongs in this league."

Robinson bulled his way onto the Lakers' roster with his offensive rebounding, energy and toughness. The Kansas product didn't know he had made it until Monday morning, leaving him to endure a sleepless night before reporting to practice.

"It was definitely something we weren't planning on before training camp started," Walton said. "(Robinson) definitely earned a spot. It was just trying to find a way to get him a spot."