Isn't he getting to the year by year phase of his career. Hopefully Boras would let him sign a 1 or 2 year deal if he's wanting to stay.
I'm going off Cot's. If I read it right, his deal at this point is $15MM a year for 2021-2028. In the 2019-21 portion of the contract, he gets $15MM a year from his $50MM signing bonus, while his $35MM a year for 2019-21 is deferred no interest to 2022-2028 at $15MM a year. I didn't read it close enough to check whether anything is due this year from the salaries his first 4 years.
Edit - checking cot's, essentially the way the deal is structured I think he spread the $210 MM from 2015-2021 out as $15MM a year from 2015-28 (14 years). On paper, he got a $50MM signing bonus ($5MM up front, $15MM/yr for 2019-21), and salaries of $10M, then 3 years of $15MM, then 3 years of $35MM. The last 3 years are all deferred to $15M a year for 2022-28.
https://legacy.baseballprospectus.com/compensation/cots/national-league/washington-nationals/