Cardinals made the final piece of ill-fated trade free for rest of MLB to claim

Early in the 2023 offseason, it was determined that it would be best for outfielder Tyler O'Neill and the St. Louis Cardinals to part ways. The oft-injured outfielder fell out of favor with manager Oli Marmol after demonstrating what was viewed as a lack of hustle, and in turn, struggled through the remainder of the season.

The Cardinals looked to be getting a future five-tool player but health concerns and clubhouse issues limited his long-term success

Once a consensus top-100 prospect, the Cardinals received then-minor-leaguer Tyler O'Neill from the Seattle Mariners in a simple one-for-one player swap of young starter Marco Gonzalez. The Cardinals were dealing from a position of depth to try and re-tool their future outfield. Gonzalez would go on to be the Opening Day starter for the Mariners three times while O'Neill quickly became a fan favorite due to his five-tool potential.

O'Neill made his major league debut the following season but spent much of the campaign shuttling between Memphis. The next two seasons saw limited time in the bigs for the outfielder, due to what would eventually become a worrisome pattern, as he ended up on the injured list multiple times each of those years.

2021 was a different story. O'Neill came into camp healthy and confident and seemed ready to make good on his potential. While he still missed some time, O'Neill played in a career-high 138 games and finished 8th in the MVP voting after he put together a .286/.352/.560 slash line with 34 home runs and 15 stolen bases and won his second consecutive Gold Glove.

The middle of the Cardinals lineup looked to be set for the future with O'Neill, Nolan Arenado, and Paul Goldschmidt each popping 30+ homers for St. Louis that season. Unfortunately for all parties, injuries again came to bite the outfielder in 2022, who was limited to 96 games and ended the season with a disappointing .228 average and 15 homers. Heading into 2023, O'Neill vowed to stay healthy and changed his workout routine while also opening himself up to play center field for the Cardinals.

Enter the drama. In early April, O'Neill appeared to have a chance to score on a Brendan Donovan hit but looked to be hesitant (or not hustling) around third base and was thrown out easily at the plate. Marmol was not happy with the perceived lack of effort and publicly called out the outfielder, who of course had to respond publicly with his disagreement. The team's handling of the situation drew local and national headlines. To make matters worse for O'Neill, his health was again short-lived as a lower back strain sidelined him in early May. It was thought he would return shortly after, but after a month and a half of little progress, the Cardinals shifted him to the 60-day injured list before finally making his return to the team in mid-July. O'Neill never really got it going again before a foot sprain suffered in September ended his season after just 72 games.

At this point, it was decided that it would be best for both sides to cut ties and O'Neill was sent to Boston in a deal that returned relievers Nick Robertson and Victor Santos. While it did not appear the Cardinals received much back, fans and media both agreed that this was what was best at the time and the team got what they could back.

So how did O'Neill's debut season with Boston go? Well, he hit a homer on Opening Day so that should have been an omen for things to come as fans immediately switched from "good riddance" to "here we go again" and he bounced back in a big way with 30 homers in 113 games. He then parlayed his big power season into a 3 year, $49.5 million deal with the Baltimore Orioles.

The Cardinals' return on investment? Robertson pitched 12.1 underwhelming innings for the team, and after riding the Memphis shuttle a few times, was eventually DFA'd in August before latching on with the Angels and then the Blue Jays. Surely Santos provided some value then, right? Not so much. The Dominican right-hander pitched in 33 games for Memphis but went 6-7 with a 5.61 ERA. Santos then went to the Dominican Winter League this offseason and performed much better over his next 23.1 innings as he put up a 1.54 ERA. It seemed as if St. Louis was finally going to get some big league contribution from the trade, but it was announced in late January that they released the righty. Most recently, the Cardinals re-signed Santos to a two-year minor league deal as he suffered an apparent injury in the winter league and is expected to miss the entire 2025 season.

Tyler O'Neill's tenure in St. Louis now adds to the growing list of mistakes the organization has made with their outfielders despite overall feelings that the trade was best for both sides. Unfortunately, he made good on his power potential while the Cardinals received next to nothing back from their acquired pieces. With Santos expected to miss all of 2025, the book is pretty much closed on the O'Neill era in St. Louis.