He is not really being blocked by Herrera.
Solano (24 in August) is the primary starter in Syracuse (of late he is getting the majority of the starts)
Montz (25 yesterday) is the primary starter in Harrisburg (and still on 40-man)
Rooney (23) is the primary starter in Potomac
Norris (20) is the primary starter in Hagerstown
Norris would take playing time away from Rooney unless you bump him to Harrisburg, then Rooney would be taking playing time away from Montz unless you bump him to Syracuse, then he would be taking playing time away from Solano. All four are still viable catcher options with Solano, Montz and Rooney as backups and Norris as a potential starter (if he improves defensively behind the plate).
It's not Herrera blocking things