The 28-year-old, who left Millwall by mutual consent in December, is now living in the Midlands and was offered to Forest by his agent.
He managed to score four goals in 16 games during his four month stay at The New Den but left because of family reasons.
It is believed a pay-per-play deal was discussed but Whelan is now looking to secure a deal with Stoke City if he can impress on trial.