Two things playing against Brosmer seeing the field:
1) Do you really want to put him behind the offensive line that got McCarthy smished? Wentz was more or less signed to be the sacrificial lamb in this specific case.
2) There isn't a QB controversy and the Vikings don't want one. I think the last thing the organization wants, only two games into their (potential) franchise QBs career, is to have an undrafted rookie come in and show out better than the guy they invested a lot of draft capital in.
That said.....hopefully Wentz looks terrible and forces the Vikes hand. It would be pretty awesome to see Brosmer take the field for the Vikings in games that matter.