The Knicks and Luc Longley are discussing an injury buyout for the three years and $20.7 million remaining on the ailing 32-year-old center’s contract, league sources acknowledged.

Longley, acquired in the four-team swap that sent Patrick Ewing to Seattle last year, played in just 25 games for the Knicks because of an assortment of ankle, knee and back ailments. His degenerative left ankle condition is showing no signs of improvement and through the buyout settlement, Longley would retire.