Oh, well, never mind. You actually think he didn't have an awful rookie season. His rookie season by any metric was indeed awful, and he earned less and less snaps as the season wore on. While I also would have liked to leave him in there to take his licks and learn on the job, he was overwhelmed and not doing well whatsoever when he started getting less playing time. I don't think there's a rational argument to be made that he had an average season as a rookie.
How do you quantify that? I don't recall anything in games that justified his drop in snaps.
In 220 snaps (which is less than 4 games worth) he had 25 tackles, allowed 57% completion at only 4.9 yards per target in coverage for a 94 passer rating (which is league average), he only missed 7% of tackles which is comparible to anyone at the position, had one TFL and 3 PD's.
If we extrapolate that out he would have had 120 tackles, 5 TFLs, 13 PDs, and only 330 yards in coverage allowed.
All in all not a vast difference to this year.
The argument seems to be "Well he lost snaps so he must have been bad" where I think Vance just screwed up and prefered vets.