The 28 year old O’Neill was acquired by the Cardinals from the Seattle Mariners in 2017 for Marco Gonzales. A former consensus top 100 prospect, he had a nice debut in 2018, putting up an 803 OPS in 61 games, and then struggled offensively in 2019 and 2020. 2021 saw what appeared to be a breakout for O’Neill, as he put up a 6.1 bWAR with a 912 OPS while finishing 8th in the National League MVP voting. He has had a 707 OPS the past two years, however, and has been the subject of trade rumors for much of that time.
Boston didn’t give up much to get him — Robertson was part of the return from Los Angeles when the BoSox sent Kike Hernandez to the Dodgers this past summer. A reliever, he put up a 6.04 ERA in 22 innings in the majors and a 3.16 ERA in 42 AAA innings. Santos is a 23 year old starting pitcher who missed all of 2023 due to injury. He was acquired from the Philadelphia Phillies in 2021 as the player to be named later in the deal that sent the immortal C.J. Chatham to the City of Brotherly Love.
This is kind of a weird deal. O’Neill is in his final year of arbitration eligibility, and so the Red Sox were able to acquire him for a couple of fringey arms. However, just a few days ago, they traded Alex Verdugo, their own outfielder who has disappointed offensively the last couple of seasons, and who was entering his final year of arbitration eligibility. Boston sent Verdugo to the New York Yankees in exchange for three fringey arms — Richard Fitts, Nicholas Judice and Greg Weissert.