Good assessment. Mateo (who's in the process of adjusting his mechanics) should not have been used in such a high stress situation.

Quoted: This is why I'm not a big fan of mid-season mechanical adjustments. Not only does a pitcher have less time to work in the bullpen and concentrate on one particular facet of his delivery, but he's also at risk of stunting (or even erasing) his progress by being brought into a situation he's not ready to face.