tbf I get his stance here, he has been open about being a Barca fan,and he rejected us for BVB joining them for 15M.
Now is the perfect time for him to be Barca player,club admire him, starting slot is open. club is willing to give them 400% profit at least (if it is 90M deal,since Rennes get 25% of any deal) and yet Dortmud (who has long history of selling their best player even to their rivals and who hasn't sold any important player this season) are trying to prevent the deal from happening. I would be crazy if I were him to be honest