The 24-year-old, who was given the captain's armband under Kinnear at Kenilworth Road, has a good reputation as a holding midfielder who can chip in with the occasional goal.
Luton boss Mike Newell told the Luton News: "I'm convinced he'll go to Forest or Leeds if they make him an offer, which I'm sure they will."
Spring is currently out-of-contract and arrived on the Luton scene through their youth ranks.