Well if we are to believe rumors the bonuses would be comprised of the appearances he makes over the next 3 years. 5m per year dependent on the appearances
the majority of the bonuses in an eventual offer should be tied to the 1st year of his contract though. we have concerns of his current injury (we are not sure if it is fully healed i guess) so if that injury is completely behind him then he should be able to meet the bonuses for his 1st season here. after that, next summer or during next 2 seasons, no one can know what will happen and he might suffer some new injury (not impossible considering the injury problems we suffered last and this summer) which wouldnt be Schalkes fault and would deny them 5-10M.
however, if they seriously are asking for 40-45M as Nostradamus is saying, then screw them, as we will never pay that even with bonuses
we still can sign Saponara or some CM/AM like Eriksen, Witsel or even some CM depth buy like that Marseille kid, Illarra etc.
or wait for City/PSG to get someone and try for Nasri or Pastore/Lavezzi. maybe Fekir or Felipe Anderson but that would require serious overpaying so... yeah youre right, no AM