How about a comp with Seattle righthander Mike Leake, who is one year older (and seven inches shorter) than Rick Porcello?
This year's bWAR and fWAR are contrasting:
RP 0.3 bWAR, 1.1 fWAR
ML 1.8 bWAR, 0.2 fWAR*
Apparently value is in the eye of the beholder.
For their careers:
RP 325 G, 321 GS, 1943.2 IP, 101 ERA+, 18.9 bWAR, 27.1 fWAR
ML 283 G, 278 GS, 1720.2 IP, 99 ERA+, 14.4 bWAR, 17.3 fWAR*
Following the 2015 season the St. Louis Cardinals signed Leake to a five-year, $80 million contract. In 106 starts since (not counting Sunday), Leake had posted 7.9 fWAR, valued at $63 million, over nearly three and a half seasons.
Four months later the Red Sox signed Porcello to a four-year, $82.5 million extension that covered his first four free agent seasons. In 113 starts since, Porcello has posted 10.5 fWAR, valued at $84.5 million, including his Cy Young 2016 season.
Since the start of the 2017 season, Porcello and Leake (and David Price) have each posted 5.4 fWAR:
https://www.fangraphs.com/leaders.aspx?pos=all&stats=pit&lg=all&qual=y&type=8&season=2019&month=0&season1=2017&ind=0&team=&rost=&age=&filter=&players=&startdate=&enddate=&page=2_30
Some have suggested that Leake's contract is under water with roughly a net $27 million owed through the 2020 season.
Feedback is welcome.
* the numbers do not include Leake's 7 IP, 2 ER, 7 H, 7 K, 0 BB performance on Sunday