So what do you want him to do, doggy? He plays the players Riley gives him. If the best player he has that can guard a C is actually a PF then that's what he has to use.
My main example is Duncan. Did you think him being a C and Robinson also being a C was gonna cause Popovic to bench one of them?
NO. He had 2 centers so he used one to guard a C and the other to guard a PF. Duncan has never been and will never be a PF. As a coach you use what you have and you TRY your best to make it work. Riley, the last 3 years, has failed to land us a rim protector and rebounder. This is on Riley. If you ask me Spo has done a good job adjusting