The Mariners and pitcher Luis Castillo agreed to a five-year extension worth $108 million.

The contract, which includes a vesting option that could take its total value to $133 million, buys out four years of free agency for the 29-year-old, who has been dominant in eight starts since joining Seattle before the Aug. 2 trade deadline. In 54 innings, Castillo has struck out 64, walked 13 and allowed just five home runs with a 2.83 ERA — even better than the 2.86 ERA he posted in 14 starts with the Cincinnati Reds and a key element in helping push the Mariners to the precipice of their first playoff berth in 21 years.

A two-time All-Star, Castillo will be paid on an annual basis among the upper echelon of pitchers. The deal includes a $7 million signing bonus, a $10 million salary for next season — when he was due to make around $12 million in his final arbitration season before reaching free agency — and annual salaries of $22.75 million from 2024 to ’27.

ESPN.com

Castillo averaged three fWAR a year over his six season career. I estimate his WAR over the time of the deal at 13.2, making the contract worth about $8.2 million per WAR. That’s pretty good for a non-free agent signing. Salaries may indeed be on the way up.