The New Zealand international has scored three times and led the line with increasing authority since joining Middlesbrough from Celtic on a short-term deal in January.
West Brom boss Roberto Di Matteo and Forest's Billy Davies have both noted his impact at The Riverside, and impending availability on a free transfer, and are ready to offer him a fresh start at the end of the season.
Wanted: Killen (right) has alerted Forest and the Baggies
With the two Championship sides seemingly locked in a straight fight for second place, at least one of them should be able to add the extra attraction of Barclays Premier League football, a factor that could prove decisive in his deliberations as he heads for the World Cup in South Africa.
Middlesbrough are expected to respond by putting together a package to try and keep him on Teesside after being impressed with the way he has spearheaded a revival that has lifted them to within sight of the play-offs.
Newcastle 2 Forest 0: Jose's big night - Enrique scores his first ever goalReading 1 West Brom 1: Tamas to the rescue but Carson is the Albion heroWatford 1 Middlesbrough 1: Sub Lita strikes to salvage a point for BoroAll the fizz of the Coca-Cola Football League: Austin living a fairytale
Source: Daily Mail
Source: Daily Mail