This is a good point, but I'm not exclusively talking about a negotiating window. And look, perhaps Skubal is just a pipe dream and probably is but its' the principal of it. The Sox have their own internal evaluation system and maybe there's another pitcher out there who is young and they think is going to be an elite pitcher going forward who they can sign for Crochet money. IDK who that is. But if you believe in a guy and you want to pay X dollars and they want to make Y and the gap is small......you can take the risk of aquiring them knowing that you should be able to work out a deal with them.
Maybe the Red Sox think SKubal is the best pitcher on the planet and 400M is worth it, maybe 400M is the price Skubal is asking for as a starting point and would actually settle at 350. But I believe these teams know what players want, and should have a pretty damn good ideal what their odds are of signing them to an extension when trading them. I don't believe ANY player is unsignable for the right price.
Obviously, some teams do this poorly and fail to sign a player. A prime example of this is the New York Yankees trading for one year of Juan Soto. There is risk, you have to be willing to assume risk but you can take calculated risks. I wonder if the Yankees knew SOtos numbers and just didn't care or if that number changed when he got to NY. I don't know.
What I do know is the Sox need starting pitching.