54 is playable, especially if you play 3-2 and can pair him with a strong 4. I'd hesitate to stick him at the 5 in a 2-3, though, unless the opposing center is not an offensive threat.

Are you implying that the center matchups against the center in the 2-3 zone?

The center stands alone closest to the basket in the 2-3.  So I suppose the center defends the player with the most low post threat.

I may look at it wrong but in a 3-2 i would want two very strong defenders at the PF and C since their defensive ratings are averaged.  In a 2-3 I would want a very strong defender at the C since he stands alone and is not averaged with another player.

Hell, I just always want strong defenders averaged or not

I think, think, BLK is more important  than normal for the 5 position in the 2-3.

Yeah, it's not so much that he's only guarding the opposing center, it's that he's alone in the 2-3. I agree BLK is more important for a C playing the 2-3. But I also want him to be strong defensively, or he's likely to get limited by foul trouble. If he's playing a 3-2 with a strong defender (In DII, I consider a strong low post defender as along the lines of 70/80 Ath/Def) I'm not worried about his 54 Def too much. His elite rebounding will make him an asset.