Kyle Tucker was a first time All-Star in 2022, but his perplexing defensive regression will keep him off this year's team. Tucker posted 16 defensive runs saved last year and was in the 89th percentile in outs above average. This year he is worth -5 defensive runs saved and is in the fourth percentile in outs above average. That's taken quite a toll on his WAR, and he hasn't done quite enough at the plate to overcome his defensive shortcomings.
Alex Bregman will also miss out on the festivities this year, having gone through just too big of a slump to overcome. His 1.2 fWAR is sixth among AL thirrd basemen while his107 WRC+ is seventh. He's had a solid, if not unspectacular start to the season, and if he finishes with a strong second half as he usually does, we'll likely look back and wonder how the 2018 All-Star Game MVP didn't make more All-Star games, but until he hits with consistency in the first half, he won't make many more appearances.
Phil Maton, Bryan Abreu and Hector Neris have been lights out as a reliever, but it's incredibly difficult for relievers to make the cut. All three have had great starts to their season, but would be unlikely to bump Yennier Cano or Felix Bautista off the roster.
Hunter Brown will likely be a staple of AL All-Star games moving forward, and his 1.7 fWAR ranks eighth among AL starters, but a couple of bad starts have inflated his ERA to 3.69. He's got a compelling case, but look for 2024 to be the first time Brown represents the Astros as an All-Star.