the school is blocking any potential transfer to Arizona State, Arizona, or any ACC school.
I understand blocking a move to an ACC school since the Panthers will be leaving the Big East to join the ACC. Normally any school on a future schedule would be blocked but Arizona or Arizona State don't fit the description. The reasons why they're blocked is because the coaches at the schools have Pittsburgh connections.
Arizona State boss Todd Graham left Pittsburgh for Tempe after one season in the Steel city. So there is some animosity there. Graham and his staff recruited Shell and it was reported that Shell was leaning towards the Sun Devils.
Current Pitt coach Paul Chryst has to sign off on the transfer, but won't do it if it's to Arizona or Arizona State. Arizona has former Pitt coaches on their staff so that's the reasoning behind that.
I could understand if he wanted to transfer within the conference and he could come back to haunt you. I would block that, but i don't understand why he won't let him go play for the coach that recruited him. I know it's like poaching but coaches do it all the time when they leave a school and are recruiting a player and said player ends up at the coach's new school. You think John Wall was actually going to Kentucky before John Calipari got there? Me neither.
Coaches have the freedom to leave any time without anyone blocking their path, let the kid go to where he wants to play.