He must be quite certain that he can sign another and better contract elsewhere, otherwise I assume he wouldn't have turned down the offer, or?
That is 240,000 Euro per week, which is 12.5 million Euros per year. Could be possible that he goes to another English club? Or is Bayern Munich even involved?
There are lot of big teams which are in need of a good solid central defender and I think lot of those teams are keeping an eye on this situation. Reports were that Real Madrid are interested in Rudiger and they can give him a good offer as he seeks. Another English club? Possible but don't think so. Players usually respect the club so no chance of going into big-6. So either it's extension at Chelsea or move to New league in Spain, Germany..