#1 - Sonny Gray
Sonny Gray's arrival as the first true ace the Cardinals have had since 2019 Jack Flaherty is a much-needed addition for a staff that was awful in almost every way last season. However, because the Cardinals failed to pair Gray with another frontline starter this offseason, they're relying heavily upon him as a stopper. If Gray were to suffer an injury or regress, it would spell disaster for the Cardinals in 2024 and beyond.
In their past few postseason appearances, the Cardinals have trotted out Kwang Hyun Kim, Adam Wainwright, and Jose Quintana as their Game 1 starters. What did all three series have in common? The Cardinals were unceremoniously eliminated in the first round. With a true ace in Sonny Gray ready for the Postseason, the Cardinals just may be ready to contend in the playoffs. Gray showed this potential with the Twins leading them to their first postseason victory in a decade, so I'm optimistic he'll lead the Cardinals to similar fortunes in 2024. However, without him, this team is doomed to repeat 2023.
The rest of the rotation in Miles Mikolas, Kyle Gibson, Lance Lynn, and Steven Matz just can't sustain itself without Gray. I've been extremely vocal in my desire for the Cardinals to add a sixth starting pitcher to pair with Sonny Gray at the head of the staff, but it doesn't look like that will happen until at least the Trade Deadline. Until then, Cardinals fans will have to hold their breath that Gray stays healthy and can recreate what made him so special as the 2nd-place AL Cy Young finisher last season.