I managed to get them documented
As far as I can tell, it's one of those things where he's technically correct but it's not nearly as big of a deal as it's made out to be.
Average grade in conference play:
Jaimes - 61.3
Hixon - 57.4
Jurgens - 54.4
Wilson - 55.9
Farniok - 62.5
Since Jurgens had a terrible grade against tOSU, here are the averages after that game:
Jaimes - 61.7
Hixon - 56.9
Jurgens - 56.8
Wilson - 56.5
Farniok - 65.8
And, just to give a little more picture of progress, here are the grades from the last two games:
Jaimes - 69.5
Hixon - 53.5
Jurgens - 63.6
Wilson - 57.2
Farniok - 64.9
So technically Jurgens was the lowest-graded lineman in conference play. But all three of the interior guys are pretty close. After tOSU, they are all basically identical, though Jurgens is technically slightly better than Wilson. And over the last two games Jurgens is actually quite a bit better than both.
So it would appear that he was getting significantly better as the year went on. Which would seem to show that Frost made the correct decision.
And, of course, none of that has anything to do with the coaches making "hard decisions". That would imply that whoever the backup center is would be doing a better job. Which none of that gives any insight into.