In four seasons with the Philadelphia 76ers, Tobias Harris has seen his production drop every year, posting just 14.7 points per game this season. While Harris was bound to underperform his five-year, $180M contract, he was at least a serviceable player. That isn't as much the case this season, and he is entering the final year of his contract, in which he will earn nearly $40M. With a massive expiring deal, the Sixers could finally trade him, but it may be more complicated than it sounds with the new CBA.
The Sixers are in the luxury tax. That would still be the case even if James Harden left this summer. If that happened, it would force the 76ers to rebuild on the fly and require more cap flexibility than they currently have. Getting rid of a negative asset in Harris would help. That's where the Spurs come in; they could trade McDermott's expiring contract for Harris' while eating the $25.5M difference in exchange for a 2024 first-round pick. San Antonio could waive Harris after the deal, and his contract would still count toward the team meeting the minimum salary cap threshold.
It would also clear a roster spot and make way for a younger player. Much like Harris, the Spurs likely won't bring McDermott back after next season, making him expendable. If they can get a first-round pick in a deal for him, it would be hard to pass up, and it would also allow the team to put their massive cap space to good use.