Would Knicks want Robin Lopez back? I know Willy H. is the future center but he's still young at 23 and could need more time to develop. RoLo played really well with KP during Porzingis' rookie season.
Rockets get: Melo
Bulls get: Ryan Anderson, Shawn Long, Tim Quarterman
Knicks get: Robin Lopez, Jerian Grant, Denzel Valentine, Rocket's first rounder?
http://basketball.realgm.com/tradechecker/saved_trade/6908748Bulls are currently only at $73m in salary without Mirotic, way under the salary floor. Anderson is a better shooter so maybe they won't need to sign Mirotic if they trade for Ryan. Felicio could be their starting center with Markkanen and Portis backing up both 4 and 5 spots.
Knicks get a couple of young players in Grant (also a former Knick) and Valentine and a veteran dependable big man in Lopez who is familiar with the team. And no long term contracts as Lopez is only signed 2 more years at under $15m per.