The 'clause' will be if club a, b or c pay at least x you can go.
There's too much talk of some kind of clause for there to be no truth in it.
Ultimately it doesn't matter what it contains exactly, Mac was always leaving this summer, he'll go for a price our board are happy with and that's that.
He's very replaceable as great as he is. Mitoma and Moises on the other hand feel almost impossible to replace. Arguably the best winger and best DM in the World right now.