Both Wednesday and Preston have been allowed to speak to the forward after having bids accepted believed to both be in the region of £1.3 million. If Henderson chooses Deepdale he will become Preston's second player after David Healy to be signed breaking the one million barrier.
Talks may well be protracted as Preston boss, Paul Simpson is currently on a pre-season tour with the first team in America. He scored 14 goals in 27 matches in Watford's promotion campaign and played a large part of their Premiership campaign but failing to regularly score. He is a well known header of the ball and scored in his debut for Watford against Preston.