In terms of MLE targets they could go after:
Mitchell Robinson 7'0, 28 years old
Sandro Mamukelashvili 6'9, 27 years old
Jusuf Nurkic 6'11, 31 years old
DeAndre Ayton 7'0, 27 years old
Mark Williams 7'1, 24 years old
Kristaps Porzingis 7'3, 30 years old
More of a PF than a center but also an option:
John Collins 6'9, 28 years old (shot 37.1, 39.9, 40.6% from three last three years)
Also can't rule out Robert Williams III return.
I want nothing to do with M Robinson, Porzingis or Timelord for the MLE. All are too injury prone. If they are at the minimum, yes. Or near the minimum, fine. But not the full MLE. We can't rely on any one of them.
Mamu can't play defense. It will be a repeat of what happened in last year's playoffs with Vooch and L Garza. TOR had to bench him in the playoffs because he couldn't play defense. San Antonio dumped him for Kornet because Mamu couldn't play defense. He is a strong offensive player but he is really only a regular season player and not a postseason player because he cannot defend anybody.
Mark Williams would be the same as M Robinson, Timelord, Porzingis. Too injury prone. It sounds like PHX are trying to re-sign him at the MLE or slightly above the MLE. So he won't be available at the MLE for us.
That is 5 of 7 out (for me). That leaves Ayton & Nurkic.
I'd take Ayton. I wouldn't be overly happy about it but I'd take him. He is at least athletic enough to play defense and he generally does play solid defense.
Not interested in Nurkic. Utah are trying to re-sign him. I don't know why. Maybe it is Kessler-insurance. They have that supersized frontcourt with Kessler, JJJ, Markkanen. I'd start them together but only play them a few minutes together. 90% of the time I'd have 2 of the 3 on the court together as the 2 bigs. No need for Nurkic. But hey, they see it differently and they want to keep him. He would likely still be gettable because I doubt they want to pay Nurkic much. I don't want to pay him either. I think he is a minimum contract to taxpayer MLE ($5-6mil?) level player at this point in his career. I also think he'll be played off the court in the playoffs by many teams due to his lack of footspeed. Not a fan of his.
So Ayton is the only 1 of the 7 centers that I would look at. Not particularly excited about that. Adequate enough I suppose. I don't think he would be happy here as a backup to Queta. Queta is better than Ayton too. So he would be the backup. An unhappy Ayton who already struggles to stay engaged and play with effort is not anything to get excited about.
I'd rather just give some guy the minimum and spend the MLE on a perimeter player. I don't think any of those guys are worth it.