The Cardinals should non-tender Andrew Knizner and John King
These are the two names I think the Cardinals are going to have the hardest time deciding what to do with, as they both played interesting roles for St. Louis in 2023, but both also give stronger reasons to be moved on from.
Let's start with Andrew Knizner, who oddly enough, was outperforming what most of us thought he would do for a large chunk of the 2023 season.
Well, Knizner had a pretty bad finish to the 2023 season, regressing to a 92 wRC+ and a -0.1 fWAR on the season. Knizner is highly respected within the Cardinals' clubhouse, and the pitching staff really likes him, but he's not worth blocking Ivan Herrera next season.
Knizner is a fine backup catcher, but Herrera is ready to provide starting catcher-type production for the Cardinals as their primary backup in 2024. In his 13 games with the Cardinals in 2023, Herrera slashed .297/,409/.351 with a 122 wRC+ and was worth 0.5 fWAR in that short time span. While we don't need to expect him to be hitting 22% above league average next year, he did mash with Memphis this year. In 83 games in Triple-A, Herrera batted .297/.451/.500 with 10 HR and 60 RBI to the tune of a .951 OPS.
Herrera has proven everything he can at the minor league levels and is now ready for significant playing time in St. Louis in 2024. Knizner is set to make $2 million in 2024, and I think the Cardinals can get some savings by non-tendering him. He could be someone worth trading, but I'm not sure how much value they would get in return.
John King, on the surface, pitched really well after coming over in the Jordan Montgomery-Chris Stratton deal at the trade deadline. Thomas Saggese and Tekoah Roby were the major pieces of that deal, but King was a nice throw-in for St. Louis to take a flyer on. A left-handed reliever who had struggled thus far in his career, King posted a 1.45 ERA in 18.2 innings for the Cardinals down the stretch.
Looking under the hood though, King provides little upside and was outperforming his underlying numbers while in St. Louis. He had a 3.85 FIP after the deadline (which was actually higher than his FIP in Texas), and still only struck out 4.8 batters per nine innings. They can keep him around if they want to and I wouldn't mind it, but if they do plan on bringing in two high-leverage relievers, clearing up the space makes sense.