I have a very good pitcher going into the last year of his contract next season. He has a max contract (20 mil) and has the option to opt out of the last year of his contract. He'll be 34 next season.
http://www.whatifsports.com/HBD/Pages/Popups/PlayerProfile.aspx?pid=2420498
He is on a very good team, that contends for the WS each season. What is chance he opts out?