OKLAHOMA CITY -- Much of the buzz around the Oklahoma City Thunder has been about Kevin Durant's return.

Serge Ibaka's comeback is nearly as important. The three-time member of the All-Defense first team and two-time league blocks leader missed the final month last season while recovering from knee surgery and, without him, Oklahoma City's defense tanked.

In 64 games with Ibaka, the Thunder allowed 99.9 points per game. In 18 games without him, Oklahoma City surrendered 108.3 points. The Thunder went 10-8 during that final stretch and missed the playoffs.

Now the 6-foot-10 power forward whom Durant calls the key to their success has been cleared to play.

"I feel great," Ibaka said at media day on Monday. "I feel great. Can't wait. I'm ready to go."

With Ibaka back, it makes everyone's job easier. The improving offensive player averaged 14.3 points and 7.8 rebounds last season.

"It just adds a different dynamic for us," Durant said. "It makes us a little bit more long and athletic. He's one of the best shot-blockers in the league. The most athletic two-way player for his position. Having him on the floor changes a lot for us. We definitely missed him last season, as you've seen, and he's the key to our success."

Ibaka's importance was notable when he was injured before the 2014 Western Conference finals against San Antonio. Ibaka suffered a left calf strain and was thought to be out for the season. He missed the first two games of the series, and San Antonio cruised in both games. A hobbled Ibaka returned, and the Thunder won Games 3 and 4 before dropping the series in six games.

This summer wasn't completely smooth for Ibaka, with the Republic of the Congo native sitting out the NBA Africa game on Aug. 1 for precautionary reasons.

"At different points during the summer, he's had some discomfort," Thunder general manager Sam Presti said. "He saw his surgeon. He's had regular checkups with his surgeon. The surgeon has continued to feel very confident and encourage him to move and play, and he's fully cleared."

Presti said Ibaka might not play every preseason game, but that's normal for the team's top players.

Last season, Ibaka made 77 3-pointers after making just 45 the previous five years. He continued to work on rounding out his game in the offseason.

"I've been working on my game, working on getting better," he said. "I don't want to complicate my game. My main focus is defense, like always. Offensively, I'm trying to do the things I've been doing in terms of getting better and better."

Ibaka's offseason work left an impression on Presti.

"I think Serge may have had the best summer of any of our players, in terms of just improvement in overall game," Presti said. "He's shooting the ball well. His passing has really improved."

Ibaka smiled when asked about Presti's comment.

"It feels great when your GM says something like that about you," he said. "That means you're working hard."