Well he is the RF. Are they really going to get anyone decent cheaper than $10 million. I mean he would have had $9.5 million this year if a full season.
Who knows, but Eaton's production this year has been pretty far from "decent." .226 with no power and average-at-best defense in RF is not a major league player, much less a $10 million player. Chances are he'd bounce back somewhat off that, but he's a player who relied on his legs to be good and is on the wrong side of 30.
Compare to Kevin Pillar, who is the same age as Eaton. Last year he had a significantly better season than Eaton is having now, and he's a much better defender. He got 1 year at $4.25 million and has essentially repeated that performance. So he's going to be out there, and is likely to be significantly less than Eaton's cost. Josh Reddick is also going to be out there. Same kinda thing: not a great year this year, not going to get $10 million, might not even get anything above a minimum deal.