The Tigers, relegated from the Barclays Premier League last season, have agreed a £1m deal for the sought-after 24-year-old.
Clucas has been the subject of offers from Chesterfield’s Sky Bet League 1 rivals Scunthorpe and Wigan this summer but neither club came anywhere near the Spireites’ valuation of the player.
Hull played a pre-season friendly game at the Proact Stadium on Tuesday night, which is when the move for the former Hereford and Mansfield man was initially proposed.
Clucas will discuss personal terms and undergo a medical on Humberside in the coming days.
The fee is a club record for Chesterfield, eclipsing the £750,000 they received from Southampton for Kevin Davies in 1997. However, they will have to pass on 15-20 per cent of it to Mansfield after their local rivals inserted a sell-on clause in the deal that took Clucas to north Derbyshire in September 2014.
Clucas, who came through the youth ranks at Leicester, is primarily a left winger but was used as a left-back and a striker by former Spireites boss Paul Cook last season.
He scored 12 goals during the 2014/15 campaign to help Chesterfield reach the play-offs.