1. Jordan Walker
Touted as the best prospect the Cardinals have had since Albert Pujols and Oscar Taveras, Jordan Walker's development at the plate was overshadowed by an early season demotion and struggles defensively in right field.
Walker finished the year with a promising .276/.342/.445 slash line with 16 HR, 51 RBIs, and a 116 wRC+ in 117 games. His bat really began to take off as he solved some of that groundball rate, posting a 120 wRC+ after being brought back up to St. Louis (dropping his league-leading 60.4% ground ball rate down to 44.2%) and a 126 wRC+ during the final 56 games of the season (with just a 39.7% ground ball rate). For Walker to emerge as a true middle-of-the-order bat, his groundball rate had to come down, and when it did, he was a monster at the plate.
The next step in his development will be raising his pull rate a bit and maintaining a high hard-hit percentage when he's not driving the ball into the ground. His hard-hit percentage dropped a bit after fixing the ground ball issue, and if he can get that back to an elite number, the sky is the limit for Walker at the plate.
Remember, Walker was just 20 years old on Opening Day, and won't turn 22 until May 22nd. He's already one of the most promising bats in all of baseball, and he's younger than pretty much every other big leaguer.
FanGraphs' ZiPS projections actually see Walker being the best hitter on the Cardinals in 2024, with a projected .269/.338/.467 slash line with 27 HR, 84 RBI, and a 122 OPS+. In fact, they are so high on him, that they have his 80th percentile projection as being a .294/.363/.523 hitter with a 142 OPS+, which would have been the 10th-best OPS+ in all of baseball in 2024.
Walker is a special hitter. He showed that as he progressed throughout the season, and the nerdy projections from objective baseball analysts predict it as well. He has the potential to leapfrog into the conversation as one of the best hitters in baseball in 2024, but at the very least, the numbers say he'll at least be a top-40 hitter in the game.
Where Walker truly needs to prove himself next year is defensively. He has all of the tools to be a good right fielder, but last year was just terrible for him out there. Things looked better as the season went on and there's a good chance he's at least average in 2024, but that has to be proven on the field.
Walker will is not free-agent eligible until at least 2030, and with the way he is trending, the Cardinals need to lock him up on a long-term deal as soon as possible. Walker is the Cardinals' next superstar, and he may become that as soon as this coming season.