A five-year contract extension for right-handed pitcher Luis Castillo will keep the prized trade-deadline acquisition part of the team's core for the foreseeable future, according to the team. According to sources, the deal is worth $108 million over the course of several years.
The contract will buy out four years of free agency for the 29-year-old, who has been dominant in eight starts since joining Seattle. Castillo has struck out 64, walked 13 and allowed just five home runs with a 2.83 earned run average, which is better than the 2.86 earned run average he posted in 14 starts with the Cincinnati Reds.
Castillo will be paid annually by the upper tier of pitchers. The deal includes a signing bonus of $7 million, a $10 million salary for next season, and an annual salary of $22.50 million over the course of a decade.


There is a variation on the sixth-year option. If Castillo undergoes elbow surgery, including Tommy John surgery, to address an issue with the ulnar collateral in his right elbow that causes him to miss at least 130 days, the Mariners receive a club option for $5 million.
Castillo will get a $1 million assignment bonus if he's moved after the 25th season, and he'll get a $25 million vest if he throws at least 180innings in the 27th season.
The Castillo deal is the latest in a flurry of spending by the Mariners, who in the winter signed American League Cy Young winnerRobbie Ray to a five-year, $115 million free agent deal and star prospect Julio Rodriguez to a deal that guarantees him at least $203 million.
Since Castillo's first start for Seattle, the M's have the third-best starter's ERA in the majors at 3.04 and the second-best in the A's at 2.70. Among Castillo, Ray, 25-year-old Logan Gilbert and 24-year-old George Kirby, theMariners' plethora of starting pitchers, which over that same time period has the fourth-best ERA in the big leagues at 2.63 makes them potentially scary.
Castillo is expected to start. The third and final wild-card spot in the American League is held by the SeattleMariners, who have a four-game lead over the Baltimore Orioles. Seattle would play a best-of- three wild-card series in Cleveland if that holds.
Seattle sought an impact arm at the deadline and paid a hefty price for Castillo, giving Cincinnati's two top prospects in the infield and starter Levi Stoudt.
Castillo had been traded four times before landing in Cincinnati where he was the front of the Reds' rotation. Castillo went 47-54 with a 3.62 earned run average in six seasons with the Reds.