I believe multiple things can be a problem at the same time. I didn't watch the game live but did when I got home. Keaschall is definitely in a phase where he needs to move farther down in the lineup. Keaschall left seven of the nine on base including twice with the bases loaded and one of those times with less than two outs. As for his defense, I have the same question that I do for Lee. Is there someone currently better that is ready to take over that position? I don't think there is and I'm willing to wait him out and see if he can improve before I replace him.
There was also a comparison to Keaschall about his ABS challenge in the 3rd inning. Some context is in order. Keaschall's ABS challenge was on a 2-2 pitch with the bases loaded and two outs that clipped the inside corner of the strike zone. For example, the April 1st game against the Royals, Wallner burned a challenge in the first inning with two out and nobody on. I don't have a problem with Keaschall's ABS challenge since the situation was at an important point in the game.
I have been highly critical of Wallner because it appears like he has no real approach at the plate and just looks lost. His walks and HBP are driving his OBP, not his ability to hit the ball. Wallner currently is Joey Gallo with worse defense, and we all know how much we loved Gallo on TD. Wallner's defense has deteriorated to the point that I'm willing to try Larnach out in the field just because I would prefer his bat, even against LHP. Even with all of that, I'm not ready to give up on Wallner yet, but it is quickly looking like he needs a reset, possibly in St. Paul.
In case you don't like my comparison to Joey Gallo, here is a comparison to Wallner this season vs. Gallo's season with the Twins. I understand that this is still early in the season, but sometimes criticisms are still warranted.