I think you've got some lofty expectations. The average SS OPS in 2017 sits at .737 with only pitchers and catchers posting lower numbers for full time roles. The average MLB OPS right now is .753, making Esco slightly better than a league average hitter. .750 is a pretty good SS if the defense is average. Defensive wizards can get away with much lower hitting aptitude. I'm not sure I'd call Escobar a core player, but given competent defense and an ability to hit slightly better than baseball, Escobar is a very valuable 10th man and could be an acceptable starter for a lot of teams. Most teams don't have a player like that on their bench. I would, without question look to see if I could lock him up for a few years beyond FA if he was interested.