4. Brady Singer
Brady Singer was one of the Royals' prized pitching prospects. After a couple of great seasons in the mid-2010's, the Royals decided to hit reset, thus trading away a handful of players and letting others walk in free agency. Singer, along with Bobby Witt Jr., was supposed to lead the Royals for the foreseeable future.
Singer has provided some strong innings for the Royals. He has yet to go down with a major injury, and he has exceeded 125 innings every season that he's been in the majors, excluding his rookie year in 2020 where he still made 12 starts. Singer has pitched as many as 153 innings just last year and is on track to surpass that many innings this year. From 2020-2022, Singer posted a 4.01 ERA, 3.84 FIP, 109 ERA+, and a 1.298 WHIP. The 2022 season was clearly his strongest. While these numbers aren't ace-type numbers, they are statistics that would surely boost the Cardinals' rotation.
The 2023 season has presented a different case for Singer. In 26 starts and 143 innings, Brady has a 5.15 ERA, 4.06 FIP, 1.315 WHIP, and is striking out batters at a career-low 7.8/9 innings rate. His April and May featured him giving up 5 earned runs or more in 7 of his 11 starts. Since the early months of the season, Singer appears to have settled down. He had two outings in August in which he pitched 7 innings or more and gave up two or fewer runs in each start.
Brady Singer is primarily a groundball pitcher, so the shift restrictions could have affected him negatively this year. He has also walked nearly 3 batters per nine innings, up from 2 batters in 2022. While he doesn't typically give up home runs, he has seen batters getting more hits off of him this year. His hard hit percentage and average exit velocity both place him in the bottom 7% of pitchers in the majors. The main culprit this year is his sinker; batters hit .255 in 2022 against it, but they are hitting .357 against it this year. Though Brady didn't throw his fastball much last year (13 pitches) and doesn't throw his sweeper much this year (14 pitches), those two pitches seem to have potential, as batters have yet to get a hit off of either pitch.
Hopefully, Singer's numbers will improve with a more stout defense behind him. Luckily, the Cardinals have a track record (though not so much this year) of performing well on the defensive side. They boast 5 starters with Gold Gloves in their trophy cases at home. The Cardinals may also be able to tap into some potential with his fastball and sweeper, though they may want him to refine his breaking pitches instead. Brady Singer isn't a free agent until 2027, so it would take a decent-sized package to pick him up in a trade this year.