If I had to guess, no time soon. The only routes I could possibly see it on are DEN-LGA and an outside chance of ORD-LGA. For ORD I only think it would happen if UA were to cut down on frequencies. IAH still flies the E175 so they don't need the capacity there. Maybe if they announced an SFO-LGA flight outside of the perimeter rule via an exemption or Saturday service it could work.

-RM