Familiar Yainer Diaz shortcoming could cause Astros real problems in 2026 and beyond

After what was a relatively down year at the plate, there has been increasing attention given to Yainer Diaz and his strike zone judgment, or lack thereof, on both sides of the ball. Diaz's offensive potential is not up for debate, and he does have a very strong throwing arm, but the guy basically refuses to take a walk, and his framing is below average at best. That lack of awareness of the strike zone could prove to be more costly in 2026 than fans realize.

The automated balls and strikes challenge system (ABS) is coming to MLB in 2026, whether anyone likes it or not. While the odds are good that the results will be positive overall from ABS, there will inevitably be hiccups, and each team will handle challenges to pitch calls differently until everyone becomes more comfortable with them.

Down at spring training, the Astros are intently preparing for the ABS system, and the early reports are that they are going to strongly discourage their pitchers from making challenges to pitches and will instead lean on their catchers to make those calls. Given Diaz's curious relationship with the strike zone, that may not be wise.

Yainer Diaz may be a liability for the Astros when it comes to the new ABS challenge system

Diaz is already going to be a bit of a challenge for the Astros on the hitting side of ABS. He has one of the worst chase rates in all of baseball, and since hitters can challenge calls, that feels like it could be a problem. However, Joe Espada can give him strict instructions as to when challenging is okay to avoid the bulk of the problem there, though he can't keep Diaz from swinging at anything remotely close.

When Diaz is in the field, the picture is murkier. Diaz not only is going to want to try and get his pitchers out and help them out, but also could challenge impulsively, given his aggressive strike zone judgment. Houston should want to empower their catchers in a vacuum, as they are usually the ones who have the best view of the pitches coming in, but Diaz is probably not the ideal candidate to have such power.

Thankfully, the Astros are making a real attempt in camp to get all of these details sorted out. If the Houston coaching staff is smart, they would be repeatedly drilling Diaz with ABS and seeing exactly how accurate his understanding of the strike zone is when he is catching. That could give everyone a better sense as to how big of a problem this could be and possibly help Diaz be a little more self-aware.