The duo have been banished from first-team training and told to train separately.
Per The Mail, no official explanation has come through from Forest about the circumstances surrounding the decision.
Both players are said to be available and can leave for any reasonable offer in January.
The source adds that it is not believed to be an issue related to behavior or physical alterations.
Both players are long serving for Forest, but have not been first choice this term, which may have led them to seek moves away.