First, Votto decision to retire will not rest on whether or not he thinks he can produce 2 WAR. That’s a bizarre line to draw. It will depend on a myriad of factors, most of them personal, most of which none of us are privy to.
Second, $13M or even $7M is a meaningful amount of money to pay when a team doesn’t have to, no matter the team. Even the Dodgers and Mets would not pick up the option if they believed they could sign Votto for less. It’s especially meaningful to the Reds who traded a useful player like Farmer over $2M.
The decision would be based on what both sides understand Votto could get on the open market. Even if he puts up 2 WAR this season, he’s not getting offered anywhere near $20M by anyone. Clayton Kershaw got a 1 year $20M deal this offseason after putting up a 3.8 WAR season, and he’s only 34. Votto over the age of 40 is getting around half that, and only if he’s good this year.