Yeah, I think MSU has a slightly better frontcourt, and much better depth. But Purdue has a much better backcourt. MSU's backcourt is serviceable shooting the ball, and pretty good in transition, but terrible in the hafl court, and can't defend to save their lives. Haas will do some damage, but I think MSU does ok down low there, but I think Purdue absolutely kills them on the perimeter.
To be honest, I don't watch a lot of teams outside Purdue, but I'm a little surprised that anyone is rating a frontcourt better than Purdue's.
Haas is a downright beast. I don't care who MSU has, if you are trying to defend him without double-teaming, he's going to eat you alive. He's got amazing post moves and can score easily on traditional centers, and athletic 5's just don't have the muscle to stop him if he gets the ball on the low block. Oh, and if you try to swarm and double-team him? He's become great at passing out of the post to a collection of the best 3-pt shooters in the country. His downside of course is *defending* athletic 5's, particularly if they're stretch 5's (guys like Wagner). He doesn't defend well away from the basket. I don't know if MSU has one of those, but I don't recall Ward being that, nor any of the other taller forwards other than JJJ.
At the 4 we have Vince Edwards, who is basically a do-it-all Swiss Army Knife player. He can take over and be the team's leading scorer on any given night, he's a solid [if not phenomenal] defender, and pretty good rebounder. He doesn't have elite athleticism, but he's no slouch. He's got pretty solid BBIQ. He might have trouble defending someone with the length and athleticism of JJJ (assuming JJJ doesn't play in the post where he'll get Haas or Haarms), or the freak athleticism of Bridges [not sure if Mathias will draw Bridges if MSU tries to play big with Ward/JJJ/Bridges?]. But he's a crafty senior who can often use his BBIQ and experience to mask some of his lack of athleticism.
And then you have Haarms backing up Haas and very occasionally playing alongside him. Haas is a more natural defender and more athletic than Haas, and at 7'3" has the length to be an elite shot-blocker. He's the most natural defensive answer to JJJ in my opinion. His liability is offense, but Purdue completely changes up their offensive scheme when he comes in for Haas, and they don't play so much through the post, so MSU has to be able to defend much differently depending on Purdue's personnel.
As you point out, we don't have great depth. Beyond Haas/Haarms we have Jacquil Taylor, a long athletic 5 but who doesn't get many minutes [partly plagued by 3 years of injuries cutting into his practice and development], and Grady Eifert, a preferred walk-on who plays above his talent level but is really only suitable for spot minutes when Vince is gassed.
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I think MSU has a hard task defensively. If you try to play Haas straight up, I'm not sure there's anyone on MSU's roster than can defend him. If you try to double him, those perimeter defenders you malign are short one man against a floor full of capable shooters. Heck, if the perimeter defense is as bad as you suggest, you might still give up too much to our shooters without doubling Haas. Although Haas has had quiet games this year, it's always been when people try to double-team him, and those are the games that our shooters go nuts. It's not that he's not helping the offense when he has a quiet night, it's that he's drawing so much attention that he's opening things up for others.
On the other end is where it'll be hardest for Purdue. MSU has the length and athleticism that has traditionally given Painter teams fits. The strategy has to be to draw Haas out of the paint to open up driving lanes, and attack with your athleticism. Yet from what I've seen, I'm not sure MSU has always done this. I seem to remember the big knock on Bridges being that he should be just abusing people off the dribble with his size and freakish athleticism, but he seems to be content jacking up 3's. But this might be one of the few games where you actually see some "twin towers" going on with Haas down low against Ward, Haarms chasing JJJ around the perimeter, and Edwards trying to keep Bridges from getting the ball down low and cutting where he can attack. The question is whether Haas can play enough minutes [he typically plays only 20-25 per game] in that kind of scenario, and whether Purdue can find ways to exploit MSU offensively if they've got both bigs on the floor [Haarms *can* shoot, but he hasn't quite found his groove yet].