How does Bruno play PF?
What skills does he have? Can he shoot? How well can he shoot? How much distance and how effective? Can he dribble the ball? Can he pass the ball? Does he have the skill to be a forward? What does he do to help the team?
The PF position nowadays is highly skilled and from what I have seen Bruno is low skilled center nevermind skilled enough to play PF.
Do Parker or GWilliams play PF? How about Horford or RWilliams? How about Tatum? My point is I don't think this matters. If you are going to have a young player on the end of the bench, why not have it be an athletic big on a min contract, even if you aren't sure if he is a PF or C? He shot 30% from 3 in college but are you really worried that your 3rd string PF can't shoot 3s? In college he shot 60% overall and about 50% in two seasons in ATL, probably mostly dunks and put backs. If he can defend reliably and not turn the ball over, I am fine with that for a 3rd string PF. None of our current or recent bigs are "highly skilled", how can you expect the 3rd string PF on a min contract to be highly skilled? I am fine using this slot on a player like Bruno.
Is Jabari Parker a PF? Yes, it is his best position. He can play some SF too but primarily he is a PF. He is already at a speed deficit (laterally) at PF and struggles to defend quick players there which hurts him far more when he slides down a slot. He is unable to play C for any extended stretch because of his bad defense and lack of shot-blocking.
Is Grant Williams a PF? Yes, he is a PF/C. He has physical and skill limitations at PF that limit his capacity there. He also has utility at C as an undersized non-shot blocking position based defender. His superior physical strength helps him match up well against bigger bodies and his lateral quickness is very good for a center (v.good at defending high post Cs). His skill level in the high post becomes an asset at center (offensive facilitator) whereas it is below average for a PF.
Is Horford a PF? Yes but not that good at it anymore. He is slowing down and not as effective defensively there anymore. His skill-level is at best average and probably a tad below average due to his slow shot release, reluctant shooting and limited ability to drive on smaller quicker defenders. Horford is primarily a center at this juncture in his career.
Is Tatum a PF? He is brilliant at both the SF and PF positions. I have no qualms with him in either spot.
Is Robert Williams a PF? No, he can't shoot. He is instantly one of the least skilled and largest offensive liabilities in the league at PF. His best talents defensively are near the basket (shot-blocking) which makes him far better suited at center than at PF where he spends more time on the perimeter not using his defensive strengths. He is an extremely limited player at PF and should not play there.
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Every forward in today's NBA should be able to shoot. Otherwise, they are an offensive liability. To be an average offensive PF you also need to have some capacity to dribble and pass. Defensively, you need to be able to cover perimeter shooters who can shoot, handle and pass. Those are the strengths you need to be an effective PF.
Most centers today are unable to slide down to PF because they lack the skill-level offensively and are out of their comfort zone defensively by having to defend further away from the rim and defend far more skilled athletic opponents.
Low skilled PFs are dinosaurs. They are more extinct than the much publicized dinosaur centers who get all the attention but truthfully the PF position has changed even more. Gone are all the plodders (there are still some at C) and gone are all the garbage men (there are still some at C).