Per Rosenthal. He has an opt out clause after 4 years as well.
Robert Raiola, CPA @SportsTaxMan 1m
Andrew Wharton @AWharton757 15m#Yankees sign P. TANAKA for 7 years $155M. Over the next 7 years he will make an average of $120,999 per #MLB in season day.
So while Tanaka is just 25, he's got some mileage. His IP put him at 69th among active pitchers.