The injury bug
By the time Matz returned to the team, it was already late July. Most fans weren't thrilled to see him back in the rotation, as the Cardinals had pitched well in his absence. Matz, to his credit, actually looked really good. He was cruising in the sixth, having allowed just two runs and having racked up seven strikeouts. His day ended abruptly when he mishandled a slow rolling ball, tearing a ligament in his knee. Matz was sidelined yet again, and this time it seemed his season may be over.
The lefty worked his way back and managed to pitch out of the bullpen, in late September. He strung together five excellent appearances, but these were mostly glossed over. Matz was already seen as an ineffective and injury-prone player. In the minds of most fans, signing him was a mistake. Matz had provided just 48 innings of work. Even when on the field, he was ineffective, as evidenced by his 5.25 ERA.
It's not like Matz didn't come with a long injury history either. He's had Tommy John surgery along with numerous other issues. Before becoming a Cardinal, Matz had seen the IL at least ten times. To many Cardinal fans, this was to be expected. If they had seen it coming so easily, why hadn't the front office? They also saw Matz as a primary reason the team couldn't spend elsewhere. Matz, at 44 MM, wasn't exactly cheap for a mid-market team like St. Louis. He was and still is one of the Cardinals' larger financial commitments.