[CardinalSagehen]

Am I the only one on this board who saw the Mercury story that said Costello is between questionable and probable for Arizona, given he has practiced this week?

No, but that statement is somewhat open to interpretation.  

R.J. Abeytia seems to have the most current data on this, and he reported the same status that you mentioned above after Wednesday's practice.  Just a few hours ago, however, he posted the following: 
[twitter]https://twitter.com/RJ_Abeytia/status/1187811289701085184?s=20[/twitter]
All of that said, my gut feel is the same as yours - I expect KJ tomorrow. I don't think Shaw wants to pump-fake with KJ's availability, but he probably thinks the ambiguity could be a little annoying for Arizona's game-planning.

[CardinalSagehen]

Am I the only one on this board who saw the Mercury story that said Costello is between questionable and probable for Arizona, given he has practiced this week?

No, but that statement is somewhat open to interpretation.  

R.J. Abeytia seems to have the most current data on this, and he reported the same status that you mentioned above after Wednesday's practice.  Just a few hours ago, however, he posted the following: 
[twitter]https://twitter.com/RJ_Abeytia/status/1187811289701085184?s=20[/twitter]
All of that said, my gut feel is the same as yours - I expect KJ tomorrow. I don't think Shaw wants to pump-fake with KJ's availability, but he probably thinks the ambiguity could be a little annoying for Arizona's game-planning.