Zach was named the starter over Flacco going into the season so at least at some point not long ago, this CS believed Zach was playing better football than Joe. Credit to Joe, he bounced back well on Sunday after a poor performance in Week 1 and had a solid game with a great finish in Week 2. Maybe Zach would've played better these first 2 weeks, maybe he would've played worse, we'll never know. Like you said though, we need to see Zach turn his potential into results. The best way to know if he can do that is to get him on the field.