Mariners land closer Castillo from Rays
Castillo, 27, owns a 2.72 ERA and 0.99 WHIP with 49 strikeouts in 36 1/3 innings while locking down a team-leading 14 saves in Tampa this season.
The Mariners have been busy on the trade front this week after dealing closer Kendall Graveman to the Houston Astros - an apparently unpopular move in Seattle's clubhouse - and acquiring Tyler Anderson from the Pittsburgh Pirates.
Castillo should slot into the ninth-inning role, effectively replacing Graveman. However, Castillo has three more years of team control before being eligible for free agency in 2025, while Graveman is a free agent after the season.
Chargois, 30, has a 3.00 ERA and 0.97 WHIP in 30 innings out of the Mariners' bullpen this season. He won't be arbitration-eligible until 2023.
Shenton, 23, entered the season as Seattle's No. 17-ranked prospect, according to MLB Pipeline. However, his stock may be rising after hitting .300/.414/.566 with 12 home runs in 67 games across two minor-league levels.