When Steve Mills was Knicks president for a five-month stint during the 2013-14 season, he made a bid to trade for Syracuse product Dion Waiters, who then was with the Cavaliers. Nothing materialized, as Waiters struggled through a troubling season. Last summer, the Knicks again made a lukewarm bid for Waiters when he became a free agent, but they signed Courtney Lee instead. Waiters signed a one-year deal with the Heat. Now Waiters, coming off a career year despite injuries, is on the market again and a lot more expensive — and the Knicks have reached out again, according to a source. Waiters averaged 15.8 points on 39.5 percent shooting and dished out 4.3 assists per game for Miami. No longer are the Knicks and acting president Mills worried as to whether Waiters can conform to the triangle offense, with Phil Jackson ousted. If the Knicks renounce the rights to Derrick Rose (who, ESPN reported, will meet with the Clippers on Wednesday), they will have $15 million of cap space. Miami, which is big in the hunt to retain Waiters, waived Chris Bosh on Tuesday under the special medical agreement with the NBA that opened up $25 million in cap room.