Cardinals reliever JoJo Romero could fill a variety of roles in 2025

Entering his third full season with the St. Louis Cardinals, left-handed reliever JoJo Romero has pitched his way into becoming a reliable piece for manager Oli Marmol's bullpen. After coming over to St. Louis after a deadline swap with the Phillies, Romero has shown durability and a knack for getting tough outs late in games.

A look at Romero's performance through 2024

The 2022 trade that sent defensive specialist and depth piece Edmundo Sosa to Philadelphia was seen as a space-clearing move that did not receive much fanfare from either organization. At the time of the deal, Sosa had fallen out of favor due to a lack of offensive output, and Romero struggled in his limited appearances with the Phillies. As things tend to go when the Cardinals ship off a depth piece, Sosa did have a late-season resurgence and put up a .937 OPS after only putting up an OPS of even .800 once during his minor league career. Of course, fans could not believe the Cardinals gave up so much value for a reliever with a career 7.89 ERA whom the team sent to Triple-A. Romero did make 15 appearances for the team at the end of the season, striking out 16 batters in 14.1 innings but also walking nine hitters in that short time.

During 2023 and 2024, however, the trade began to shift more toward the Cardinals' favor. While still valuable in his role, Sosa saw his offensive production fall back toward his career norm, as he hit 17 homers with a decent .254 batting average over his next 194 games with the Phillies, which put him right about league average in terms of OPS+. Romero, though, pitched his way into high-leverage spots with a solid 2023, although he only took the mound 27 times. His numbers across the board were well above his career performance to this point, and his 2023 Baseball Savant page is full of elite ratings. Another positive note: He increased his strikeout rate from 25% to 29% and decreased his walk rate from 14% to a minuscule 7%.

2024 was where Romero took another leap. The lefty increased his sinker and slider usage with positive results, as he appeared in 65 games and tallied 30 holds, a save, and a 7-3 record, which admittedly does not mean much for a reliever. The peripherals were not as kind to Romero, as his strikeout rate took a dip to 21%, but he was able to hold his walk rate steady. A massive weapon for the reliever was his ability to get ground balls in big spots. Opposing batters put the ball on the ground 50% of the time, and Romero induced five double plays throughout the year.

Romero mainly features a 94mph sinker and an 84mph slider but also dips into a changeup and four-seam fastball. While the former fourth-round pick put up a solid 3.36 ERA in his busy 2024 season, it appears he had a bit of luck on his side. His xFIP was almost a full run higher at 4.27, and his xERA was even more concerning, at 5.14. With his decline in strikeouts, he relied heavily on hitters putting the ball in play and his defense backing him up. This worked for a majority of his appearances, but another concerning look at the numbers shows he did blow eight saves and give up eight homers through his 59 innings.

Where does Romero slot into the bullpen for 2025?

A quick look at the basic numbers would show that JoJo Romero should be a candidate for the seventh and eighth innings of close games, but a deeper dive shows some concerning results that could limit his effectiveness. Romero was outright dominant against same-handed hitters, as lefties only hit .181 with one homer and 25 strikeouts. Against righties, however, that average rose to .264, with a concerning 11 walks and seven homers surrendered.

While he put up well-above-average value in terms of ERA+ in each of his two full seasons with the Cardinals, the concerning splits may make him most valuable as a matchup reliever. 2025 projections all show that Romero should again be a valuable piece in the bullpen, as they all show an increase in his strikeout rate with a consistent mid-three ERA and opponent batting average.

With the Cardinals sitting in an awkward position in terms of their roster makeup, Romero appears ready to start the season in St. Louis and back in his setup role for closer Ryan Helsley. As the season progresses and the team starts to find its place in the standings, it is very possible that Romero becomes an attractive trade piece for almost every competitive team around the league. If the Cardinals change tune and end up shipping Helsley away, Romero could also be the first man called on to handle the ninth-inning duties.

The current St. Louis Cardinals roster has most of their positions settled with holdovers from the 2024 season, and JoJo Romero is one of the most reliable names out of the bullpen. He most likely will slot into the late-inning role at the start of the season, but potential roster or performance changes could alter his role for the Cardinals or elsewhere around the league.