If the San Antonio Spurs were going to send Kawhi Leonard to the Sixers, they did not want Markelle Fultz.
According to ESPN's Zach Lowe, the Spurs were not looking at trading for Fultz in a potential deal for Leonard.
There is no evidence that the Spurs wanted Fultz.
I’ve been told the Spurs never asked for Fultz and actively didn’t want Fultz and in fact wanted one of the two big guys.
The big guys Lowe mentions are Ben Simmons and Joel Embiid. Obviously, the Sixers were not going to trade either cornerstone big man to San Antonio which likely put the nail in the coffin on any deal between the Spurs and Sixers.
In addition, Fultz had tremendous struggles in his rookie campaign which could h ave been another reason the Spurs did not want the young NBA player. Also, the Spurs have a stock pile of shooting guards and adding Fultz may not have made any sense.
Ultimately, the Spurs traded Leonard to the Raptors (along with Danny Green) in exchange for DeMar DeRozan, Jakob Poeltl and a 2019 draft pick.