The Dutch defender suffered a long-term injury at the very start of this season.
Timber, who tore his ACL in the opening game against Nottingham Forest, wants to play before the season ends.
Timber was a guest on Frimmy's Colney Carpool and spoke about a recent training session.
Timber promptly replied "Heavy, heavy, heavy" when asked about the intensity of training.
Such a comment suggests that he may be being put through his paces to feature for the first team.