Graham had been out of the game for five months when he was signed by manager Peter Jackson in the summer, with a view to seeing him recapture the form that earned him a big money move to Wigan a few years ago.
He made two league starts for the Imps, along with seven substitute appearances in the league and another in the FA Cup, and failed to score a goal. His last appearance saw him hauled off at half time of the Imps 5-1 demolition of Accrington.
Graham has to consider himself unlucky after a couple of decent showings failed to bring him a goal.
Jackson is now hoping to sign 35-year-old striker Geoff Horsfield on a short-term deal during the transfer window