Last month, I broke down dollars per win share among current Suns players. Marcin Gortat shined by this measure as did Markieff Morris, who has the benefit (in this case) of a small salary due to his rookie contract. Channing Frye placed a respectable 4th, to go along with him being the Suns:
2nd leading rebounder
5th leading scorer
4th in player efficiency rating (PER)
5th in effective FG%
4th in win shares/48 minutes at .090 (.100 is approximate league average)
What these numbers say to me, along with watching Frye play for the Suns these last 2+ years, is that he's an excellent bench player, lackluster starter and overall average player. He sometimes plays terrible, sometimes plays great, and sometimes both in the same game (i.e. his 2-18 shooting, 14 rebound, outstanding defensive performance vs. Blake Griffin) and it averages out to, well, average.
His $5.6M salary this season is also remarkably close to the league mean average salary, which was reported to be $5.15 last season. So, we all agree that Frye will never be a star and isn't compensated like one.
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The important point here is not just to properly value Frye, but to realize that if the Suns get rid of him for the sake of cap space, they're as likely to end up with a Kwame Brown as they are to end up with a Samuel Dalembert. In other words, a crapshoot.
You can see how Frye stacks up against the middle of the road big guys at the link. Spoiler alert: he's in the middle...of the middle.
Dude is paid just right.