Like I said, with the right sort of athletic, rangy, shooting 4, it would be OK offensively to play Markannen at the 3. Although even then, in most cases that mystery 4 would probably be better suited to go to the 3 than Markannen would. Think Kawhi, LeBron, KD, DFS, Scottie Barnes, Patrick Williams, DeMar DeRozan, Jerami Grant - just looking through starting PF that could play with Markannen and in almost every case, I'd move the OTHER guy to SF

The only situation I see where I might want Markannen as a 3 would be something like if he went to the T-Wolves with KAT and Gobert or to the Cavs with Evan Mobley and Jarrett Allen (though I have a suspicion that wouldn't utilize him very well). Same story on the Hawks with John Collins and Clint Capela. Markannen probably ends up at the 3 there... but it's not an idea fit.

And this ignores the defensive issues. Markannen CAN play the 3 if it's demanded. But given the many issues it brings, it shouldn't be the norm, only for short stints against the right opponent lineups