Surely the decision on whether to include him in the team is Arteta's?
Going a bit off topic now, but if Partey does end up gone for the alleged reasons, would the club be likely to have some sort of insurance policy to cover losses in that sort of case? I assume such a thing doesn't exist but we'd be writing off a huge amount of his transfer fee we couldn't recoup any value on through playing time or sale, and would have to spend a similarly large amount to get a replacement of similar quality.
