Serge Ibaka out 4-6 weeks after undergoing knee surgery

The Oklahoma City Thunder's playoff hopes took a huge hit on Tuesday.

Power forward Serge Ibaka will miss four-to-six weeks after undergoing successful arthroscopic knee surgery, the team announced. 

Ibaka sat out the Thunder's last three games due to swelling and soreness in his knee. A report followed on Monday, suggesting Ibaka will require surgery.

If Ibaka returns in four weeks, rather than six, he could be back in time for the start of the playoffs. 

Making the postseason is no guarantee for the banged-up Thunder. The New Orleans Pelicans are hot on their heels, sitting only a half-game back for the last playoff spot while also holding the tiebreaker, should the two teams end the season tied in the standings.

Ibaka, in his sixth season with the Thunder, is posting averages of 14.3 points, 7.8 rebounds and 2.4 blocks in 33.1 minutes played. But Ibaka's importance extends beyond his averages. He's the backbone of the Thunder's defense that has kept them afloat during a tumultuous season marred by significant injuries to their superstars.

Ibaka's absence could pressure the Thunder to rush Kevin Durant back from his foot injury. Currently, Durant is not expected to return until next week. With the Thunder fighting for a playoff spot, there might not be time to wait.

The Thunder will likely slide one of Nick Collison or Steven Adams into the starting lineup, while leaning even harder on Russell Westbrook to continue his superhuman output.