If you look at the schedule and the overall state of the AFC east, next Monday's game against the Broncos is close to "must win" territory for the Pats.
One major issue the CBs had against the Chargers is that their size was badly exploited. Deltha O'Neil didn't get burned like Duane Starks and Fernando Bryant were getting burned, but his mismatch in size was exploited. While we're in some trouble facing 6'4" Brandon Marshall, the good news is that Eddie Royal might actually be a good matchup for us. He is a short, quick guy, someone that Hobbs or Wheatley should be able to handle.
I do agree that the next few weeks, including the St. Louis game, will be a big test for the young defensive backs, and letting them play man against some of the game's getter WRs might be a valuable learning experience, even if it means another painful defensive performance or two.