2. Trading Jordan Montgomery rather than extending him
We saw it with the Yankees and Aroldis Chapman in 2016 - trade your valuable expiring asset for prospects, and then look to bring them back in the offseason. The Cardinals hit the ball out of the park with their return in the Jordan Montgomery trade but have failed in the second department.
Extending Miles Mikolas last spring was a mistake, but that does not mean they could have extended Montgomery at that moment instead. Montgomery is a Boras client, so the likelihood that he was going to sign an extension before the 2023 season that would have been a good deal was slim at best.
So, once the Cardinals fell out of contention, they flipped Montgomery for Thomas Saggese, Tekoah Roby, and John King, the former two being top 100 prospects in all of baseball. That's an excellent haul for a guy who was on a heater last season and was going to hit free agency either way.
Had the Cardinals extended Montgomery, that wouldn't have been a bad move (assuming the numbers are not crazy), but they'd be without that prospect capital they were able to acquire. They should have gone out and signed Montgomery or someone else in his tier to pair with Sonny Gray this offseason, and that's where they are making a huge mistake. But trading Montgomery away instead of extending him was clearly the right decision.
I get that the Cardinals only had one starting pitcher under contract for 2024 before resigning Mikolas, but the wisest thing to do with a player like that would have been to wait and see what his year would be like. I highly doubt he would have gotten more money than St. Louis gave him even if he had a good year, and so that's where they really shot themselves in the foot in this whole process.
Still, the Cardinals have an opportunity to right their wrongs and bring back Montgomery before another team snatches him up. I like the idea of the organization having all three of Montgomery, Saggese, and Roby, and they should too.