Exactly. We have a good example in the Finals as well. Radmanovic, Walton and Ariza are a good SF rotation. Rad is a great shooter, Walton a great play-maker and Ariza a great defender. But they don't do anything else and I bet Phil Jackson would rather dump 2 of them for a player like Posey.
I remember saying before the Finals that the Lakers bench was apparently better but in the end we would win the bench battle because Posey was the best all-around player and the most versatile one and we wouldn't be playing bench vs bench 5on5 games.
Well, we agree, but I'll go one further. I'd bet that Jackson would willing dump all three (Spaceman, Jr., and Ariza) for Posey and sign a minimum guy (like, say, Matt Barnes) to fill the rest of the time. This discussion all comes down to PT. There are 240 minutes available per game. Thats six 40 minute increments. Assume for simplicity's sake the playoff starters play 40 minutes (not always true, I know, but bear with me, it does not change the argument). If you have a strong 6th man who is a combo guy (can play two positions, be it the 1/2, the 2/3, the 3/4, or the 4/5) AND you have players like Garnett and Pierce who are starters who can play multiple positions, depending on match-ups, your 6th man can play the majority of the bench minutes (my guess is about 22, or what Posey average in the playoffs). Of those 40 "bench" minutes, would you rather have Posey taking 22 and whatever rookies/min-level guys you have taking 18 (Powe, BBD, and House), or would you rather have Barnes, Ross, and the corpse of Anthony Johnson taking, say 36 of those minutes?
I go with the former. Barnes, Ross, and Johnson are not significant upgrades over Powe, BBD, and House if they are even upgrades at all (Barnes looked great two years ago, last year, not so much). Posey is the most useful player in that scenerio, playing the most minutes.