The rebuilding Seattle Mariners traded for three members of their current starting rotation -- Marco Gonzales, Justus Sheffield and Justin Dunn -- all of whom remain under team control through 2025.
In July 2017 Seattle acquired lefthander Marco Gonzales from St. Louis in exchange for outfielder Tyler O'Neil, who then was a Top 40 prospect. Since the start of 2018 season Gonzales ranks 22nd among all pitchers in fWAR.
Coming off an 89-win season in 2018, the Mariners traded lefthander James Paxton to the Yankees for lefthander Justus Sheffield, righthander Erik Swanson and outfielder Dom Thompson-Williams. Sheffield has been inconsistent in the rotation but on Sunday pitched six shutout innings, giving up four hits while striking out seven and walking none.
In the same offseason Seattle traded closer Edwin Diaz, secondbaseman Robinson Cano and cash to the Mets for outfielder Jarred Kelenic, pitchers Justin Dunn and Gerson Bautista and spare parts. Dunn has struggled in the rotation but posted a quality start last night while Kelenic is a Top 12 prospect in baseball.
Meanwhile the Mariners drafted highly regarded college pitchers in the first rounds of the drafts in 2018, 2019 and 2020. Logan Gilbert, George Kirby and Emerson Hancock have all cracked at least one Top 100 prospect list.
The rebuild can be painful as evidenced by Seattle's 94 losses last year. But patience could pay off.
Or not.