DJ played 208 snaps in the 4-3 as a mike backer in 2008.
He had a +1.8 rating and more importantly, 11 defensive stops, which is a very good stops-to-snaps ratio.
I have a hunch we're going 4-3. DJ will be just fine in this role.
Alex Smith's current 9.8 YPC is one of the lowest marks in the NFL over the last 10 seasons. Only a few QBs have been worse:
Ryan Mallett (9.8), Derek Carr (9.4), Christian Ponder (9.8), Brady Quinn (9.8), Ryan Fitzpatrick (8.6), Brodie Croyle (9.7), Charlie Frye (9.7), Bruce Gradkowski (9.4), David Carr (9.2)