We pretty much know what Mac is going to be for a few more years. Yes any player can hit the decline suddenly and at catcher it can happen even faster. But Mac WRC+ of 122, 87, 122, 123, and 119 the last 5 years. 2012 being the obvious outlier when his BABIP was 234. That's being pretty damn consistent to me. He's not the player he showed in 06 or 08 (inflated BABIP in those years) and shouldn't be paid like those years either. Mac doesn't qualify because of playing time but he would have the 5th best WRC+ among catchers and has the 3rd most homers. He's still a top catcher in the game. Might not be an all-star every year due to the emergence of Posey but he's still a 4+ win catcher. Those are extremely valuable. This team is young and good but I don't think our window is all that big. We won't be able to keep everybody. Mac makes us a better team right now and we need to take advantage of it.