Article: What Went Wrong for Erik Swanson?

[Leo Morgenstern]

Erik Swanson enjoyed his breakout campaign in 2022. Following three uneven and injury-plagued years with the Mariners, he made 57 appearances in the 2022 season, pitching to a 1.68 ERA, a 2.30 xERA, and an AL-leading 1.85 FIP. After striking out roughly 23% of his opponents from 2019-21, the 6-foot-3 righty upped his strikeout rate to 34%. Even better, he didn't have to sacrifice control to procure those extra punchouts. No AL pitcher (min. 25 IP) had both a higher strikeout rate and a lower walk rate. On top of that, Swanson gave up just one hit-by-pitch, one wild pitch, and three home runs all year. He never had so much as a 10-game stretch at any point in the season where his FIP was above league average. He never issued more than one non-intentional walk in an outing. Only once did he give up more than two hits in a game, and only twice did he give up more than one earned run. Simply put, Swanson was wholly, completely, and undeniably in control, from his first scoreless outing in April to his last in October.  

As effective as he was, Seattle mostly used him in lower-leverage spots, so he only racked up three wins, three saves, and 14 holds. Indeed, the Mariners never seemed to buy all the way in on Swanson as a back-of-the-bullpen stud. He began to see more high-leverage opportunities as the year went on, but after a few rough outings in September, he quickly lost whatever trust he had gained. In his first eight games in September, he gave up six earned runs in just under six innings of work. His ERA climbed from an MLB-leading 0.84 to 1.85. Yet, he also struck out nine of 26 batters while walking only two, giving him a 3.29 FIP, 2.82 xFIP, and 2.39 SIERA in that span. His opponents produced a .400 wOBA but just a .267 xwOBA; only one AL reliever faced more batters in that time and had a bigger mismatch between those two stats. What's more, Swanson finished the regular season on a high note, tossing five scoreless frames over his final four appearances, giving up two hits and a walk while striking out seven. Even so, the Mariners were strangely hesitant to use him in the playoffs. He didn't pitch at all in the Wild Card Series against the Blue Jays, and he didn't enter in the ALDS until the 13th inning of an 18-inning marathon in Game 3. That was partially because the Mariners had a bullpen loaded with talented arms. Still, it seemed like Swanson had fallen out of favor, at least a little bit, in the organization. 

Seattle's loss was Toronto's gain. Many Jays fans heavily criticized the Teoscar Hernández trade at the time, and I'm not here to relitigate. I'm not here to stir up controversy. But it's not controversial to say Swanson was terrific for the Blue Jays in 2023. In 66.2 innings, he pitched to a 2.97 ERA, a 3.04 xERA, and a 3.51 FIP. Those numbers don't look quite as impressive as his stats from the year before, but keep in mind that he pitched 13 more innings in a higher-leverage role at a much less pitcher-friendly home stadium. Additionally, the league-average ERA was about one-third of a run higher (3.97 in 2022, 4.33 in 2023). That's not to say everything was perfect – his strikeout rate fell to 28.6% and his walk rate rose substantially to 8.0% – but Swanson was nonetheless an excellent back-end arm. He earned a career-high four wins, four saves, and 29 holds (third in AL), and his 3.30 Win Probability Added placed him among the top 10 pitchers in the game. 

All told, from 2022-23, Swanson threw just over 120 innings with a 2.39 ERA. Only six relievers pitched to a lower ERA in at least as many innings. Only five had a higher strikeout minus walk rate (K-BB%). None had both more strikeouts and fewer walks. We're talking about elite numbers here. By the time the 2024 season rolled around, Swanson was already 30 years old, and he didn't have a long track record of success. Regardless, the Blue Jays had good reason to believe they had one of the league's better set-up men at their disposal. 

What followed was a highly disappointing performance. Forearm tightness kept Swanson on the IL for the first three weeks of the season, and while the injury didn't prove to be serious, the righty wasn't himself upon his return. After he posted a 7.27 ERA and, even more concerning, just a 17.5% strikeout rate through his first 11 games, the Blue Jays optioned him to Triple A. His struggles continued in the minors, where he gave up 24 runs (19 earned) over 17 games. His strikeout rate barely improved, and he walked almost batters as he struck out. Nevertheless, the Jays called him back up after the All-Star break, largely due to a lack of other options. 

To his credit, Swanson was much more effective in the second half (2.55 ERA), although his peripherals suggested lingering problems. He pushed his strikeout rate back up to a healthy 27.6%, but his walk rate continued to climb. He finished the season with an ERA, xERA, and FIP all over 5.00, and that doesn't even take into account his disastrous performance at Triple A. 

Then, as if he weren't enough of a wild card already, Swanson suffered another arm injury that would keep him out for Opening Day 2025: a median nerve entrapment in his right arm. The Blue Jays were left to wonder what kind of pitcher they would get upon his return. Would he rediscover his dominant set-up man form from 2022-23, or would he continue to struggle like he had in 2024?

As it turns out, the sad answer was that 2024 was just the tip of the iceberg. Swanson allowed eight runs (six earned) over 5.1 innings during his minor league rehab assignment in May. Upon his return to the majors in June, he gave up runs in four of his six outings, striking out just three of 30 batters while walking five and hitting one. A grand slam to Nick Castellanos over the weekend would turn out to be his last pitch (or, you know, his swan song) with the Jays. The front office had seen enough, and they designated the once highly effective reliever for assignment on Tuesday. His future is now up in the air.

Just a few weeks ago, I was asking if any Jays Centre writers wanted to cover how Swanson's return could energize the Blue Jays' bullpen. Today, I'm writing about the team's decision to remove him from the roster. A fall from grace of this magnitude raises two equally difficult questions: What happened to Erik Swanson, and what's next?

Unfortunately, there's no easy answer as to why Swanson has had so much trouble over the last two years. Is it injury-related? Perhaps. He has spent time on the IL in every season since 2020. Yet, if the Blue Jays' medical team had found any evidence of an injury, then surely they wouldn't have DFA'd him. The same goes for last year. If the Jays had reason to believe he hadn't fully recovered from the forearm tightness that held him back in March and April, they would have placed him on the IL instead of sending him down to Triple A. His velocity is down this year, which could be an indication of a lingering injury issue, but there was nothing unusual about his velo in 2024. In other words, that might be a piece of the puzzle, but it doesn't solve the whole thing. 

Could it be a pitch mix problem? Sure. Swanson has thrown the same three pitches for years – a splitter, a four-seam fastball, and a slider – but his usage patterns haven't been consistent. In his first year in Toronto, his splitter was his primary pitch against righties and lefties alike, but in 2024 and '25, his four-seam has taken on that job. Yet, his pitch mix over the past two years is actually quite similar to his pitch mix in 2022 with the Mariners, when he was at his best. So, the issue isn't as simple as him throwing too many fastballs and not enough splitters – especially since his fastball has been his most effective pitch the past two years.

To that point, the drop-off in his splitter's effectiveness has been Swanson's biggest problem. From 2022-23, Swanson's splitter was not only his best pitch but arguably the most valuable splitter in the league. According to Baseball Savant, the split-finger had a context-neutral run value of +2.7 runs per 100 pitches. No other pitcher (min. 100 splitters) came particularly close. In 2024-25, Swanson's opponents have laughed at his splitter for a .404 wOBA (compared to a .201 wOBA from 2022-23). The pitch has a -2.7 RV/100. In other words, it has been just as bad as it once was good. When he has tried to use his splitter to challenge hitters over the plate, they have crushed it like never before. Unfortunately, that only means he's throwing fewer splitters in the strike zone, hence his soaring walk rate. 

So, what comes next for Swanson? There's a good chance he'll be claimed on waivers. He is only owed about $1.7 million for the remainder of the season, and I wouldn't be surprised to see a team take a chance on him at that price. That said, it's more than possible no one puts in a claim. In that case, Swanson would have the option to elect free agency and look for a club willing to take him on at a cheaper price. Considering his upside, it shouldn't take him long to find a new home, but it's anyone's guess what happens after that. Will a new team be able to help Swanson return to form, or at least return to being an effective major league reliever? Or is the stuff that made him so dominant in 2022 and '23 gone forever? We'll have to wait and see. 

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[Leo Morgenstern]

I didn't mention this in the article, but I'd like to see Swanson land in Philadelphia. The Phillies have room in their bullpen, and they like a good reclamation project. And it would be interesting to watch them trying to fix Romano and Swanson.