How much would it be though?
Isn't it based on "market value"? I don't really know how it works, but if FSG were to let him run his contract down, I'd suspect a fee from arbitration would be their reasoning. They're obsessed with value and letting Sterling walk for nothing just wouldn't happen, in my opinion. Or they think playing hardball will make him sign a new contract, with a hefty buyout clause, to protect the value of their asset. If indeed FSG are serious about letting him run down his deal, Sterling is going to miss out on a lot of money, and it's likely that he just signs a deal with a buyout clause.
I mean, if someone offers 40,000,000 are we going to turn it down, get a few million, and then Sterling joins Chelsea/Man City or whoever anyway?
Based on the Suarez saga, FSG don't want to "sell to a rival" - now, that would depend on how we determine "rivals." When Arsenal wanted Suarez, they were a legitimate rival in the sense that they were competing for what FSG wanted - CL football, top 4 trophy, etc. Would they view City and Chelsea in the same light, two clubs that are almost certain to finish in the CL places every year? Also, Arsenal's offer was a complete pisstake and wasn't representative of Luis's worth, we all know that. If Arsenal, say, bid Ł75m - the fee Barca paid for Suarez - would it be the same scenario? It's hypothetical and hard to say, but I suspect we would have sold him.
Anyway, FSG kind of have a Lyon model, I think. Based on their contract situation, importance to the team, output, etc., every player on our squad has a value, and anytime someone bids over and above this value, we'll probably sell.