It's looking more and more like San Antonio swingman Kawhi Leonard will be dealt this coming offseason, and given Leonard's status as a top 10 player in the NBA - teams are already lining up to talk a trade with the Spurs, according to ESPN's Brian Windhorst. Two of those teams could very well be the Sixers and Knicks, as both teams already have young superstar players in place and will be looking for a top-level veteran to put them into true contention this summer.
Outside of maybe the Boston Celtics, the Sixers still have the most tradeable assets of any non-tanking team in the NBA. Philly currently has a top 10 2018 pick to dangle (which could improve or fall in the lottery) and it has several enticing young players it could move to sweeten a deal. Acquiring Leonard would cost a pretty penny for sure, so the Sixers would have to be willing to trade anyone outside of untouchables Ben Simmons and Joel Embiid. San Antonio would surely want to bring in Markelle Fultz, and would likely ask for Dario Saric as well. Just to make money work alone - Fultz will make 8.3 million next season and Saric will make 2.5 million - the Sixers would need to look at trading both players. Then there's the question if that would even be enough for San Antonio to bite?
Putting the sharp-shooting Leonard in the same lineup as Simmons and Embiid would immediately propel the Sixers into the NBA's elite echelon, and all signs point to Philly being in "veteran All-Star acquiring mode" this summer given all the LeBron talk. Leonard, a former NBA Finals MVP, would be one hell of a Plan B for the Sixers.
Meanwhile, the Knicks will also be looking to add an elite talent in the coming years to place next to Kristaps Porzingis. This may all be a year or two ahead of schedule for the Knicks, considering they have nowhere near the amount of tradeable assets as the Sixers or Celtics - but if New York gets lucky in the lottery (right now they're looking at just the ninth pick, albeit in a deep draft) - expect them to at least explore a Leonard trade.
The Knicks have a plethora of second round picks to help ease things financially with a trade partner, but one more year of tanking would do New York good. A package of whichever player they land in the draft this year, their own 2019 first rounder and a young player like Frank Ntilikina would command other teams' attention at the trade table.
Also working in the favor of teams like the Sixers and Knicks when it would come to a trade for Leonard is that they reside in the East. San Antonio is - needless to say - a proud franchise and would rather not re-start a franchise like the Lakers by trading Leonard there. Houston would also likely be interested in going after Leonard this summer if he is indeed on the block, but San Antonio would surely not want to ship him within state either.