Another Cardinals top pitching prospect is heading to the injured list

The St. Louis Cardinals' pitching at the major league level has seen plenty of ups and downs since the beginning of the season, but the minor league pitching staff has been hit hard once again. After Tink Hence and Cooper Hjerpe, two of the organization's top pitching prospects, ended up on the injured list, Quinn Mathews joined them after being added to the list on Monday.

Hence does not have a timetable to return after being put on the 60-day injured list, and there has not been much information about the left-handed Hjerpe other than his initial placement. In Mathews' sake, though, this seemed to be a possible outcome, as he has struggled mightily since being moved to minor league camp after his brief stay in Jupiter.

Organization #2 prospect Quinn Mathews was placed on the 7-day IL.

Mathews was not given an official diagnosis or reasoning behind the placement, but he has struggled to stay in the strike zone and throw at his usual mid-90s velocity. So far in 2025, the left-hander out of Stanford has started three games with increasingly concerning results. In his season debut, he threw four decent innings but only struck out one hitter after leading all of the minor leagues in strikeouts last season. While he has never had great command, he walked three batters and gave up four hits, which led to two runs in the loss.

When the calendar turned to April, Mathews' performances continued a downward trajectory, beginning with his start against Blue Jays affiliate Buffalo Bisons. While he only gave up one run, his pitch count was at 77 when he was pulled with two outs in the fourth inning. His pitch total skyrocketed quickly thanks to six walks and four strikeouts, but he was able to limit the damage to only one run during his outing. The six walks were the most that Mathews had given up in a start in his professional career, but he has allowed five walks three separate times.

The concern level had to hit an all-time high for the #42-ranked prospect in all of baseball during his last start. Mathews again struggled with his command but was unable to limit the damage this time thanks to five hits and two homers given up during his 2.2 innings of work. For the first time since being drafted, the lefty walked six batters in back-to-back starts. He also saw his velocity drop from mid-90s to low 90s, furthering the concern for the entire organization.

At the time of his IL placement, Mathews had pitched a total of 10.1 innings, putting up a 6.10 ERA thanks to 15 walks and 11 hits through his first three starts. To find good news in the situation, there has not been any announcement that should stress concern beyond the IL placement, and he was only put on the 7-day IL rather than the 60-day like they did with Hence. It is possible that they are giving the lefty time to rest and work on his mechanics rather than there being something seriously wrong with his body, but until an official announcement comes from the team, anything is possible.

The hope was that Quinn Mathews would make his debut in St. Louis at some point in the near-ish future, especially if the team went into full "transition" mode and dealt some of their veteran starting pitching depth away. Now, that plan hits a full stop as the minor league pitching depth will be challenged for as long as Mathews, Hence, and Hjerpe are on the shelf. Michael McGreevy and Gordon Graceffo will be the frontmen in the rotation, with Ian Bedell and Sem Robberse slotting in behind them. Those are the only pitchers to make a start so far this year, so it is right to assume that a Double-A arm could be receiving a promotion to Memphis as the organization looks to fill innings in Triple-A.