Boston Red Sox trade for former Toronto Blue Jays left-handed starting pitcher

According to ESPN's Jeff Passan, corner infield prospect Blaze Jordan is headed to the Cardinals in return.

The former Blue Jays lefty is a pure rental for the Sox, as the veteran southpaw's four-year, $44MM contract is up at season's end.

St. Louis inked Matz to that free agent deal on the heels of his successful 2021 season as a starter with the Blue Jays, but Matz has only started 36 of his 84 career games with the Cards.

Injuries and ineffectiveness have hampered his time in St. Louis, leading the Cardinals to move Matz into more of a swingman role, and he came essentially a full-time reliever this year (save for two spot starts in April).

While Matz didn't live up to the expectations of his contract, he pitched pretty well in both 2023 and during this season, as the southpaw has a 3.44 ERA over 55 frames in 2025.

Typically a good control pitcher, Matz has taken it a step further with an elite 4.0% walk rate this season, and his 5.3% barrel rate is also excellent.

This ability to limit mistakes and keep the ball on the ground (44.3% grounder rate) has helped balance out more ordinary strikeout and hard-contact rates.

Left-handed batters have only a .442 OPS against Matz this season, while righty hitters have a much more productive .814 OPS.

The gap in splits will be somewhat hard for manager Alex Cora to work around since Matz has so much value as a multi-inning reliever, yet that same durability will help out a Boston pen that has logged a lot of innings bailing out its shaky rotation.

It's possible the Sox could even turn to Matz again as a part-time starter, though the Red Sox are expected to land more significant starting help prior to today's deadline.