I'm thinking more like they aren't optimistic about Kempt coming back or getting a worthwhile transfer. If they think Re-Al can be utilized in special situations on a limited playbook, they could play him as a true freshman and redshirt Purdy, effectively putting them in different classes.
Would be a great replacement for Lanning in a goal line package or obvious running situations. With Montgomery and Re-al in the backfield, you have to respect two runners.