The 22-year-old midfielder, a member of the England Under-19s squad which won the European Championship in 2017 along with then club-mate Mason Mount, trained with his new team-mates for the first time on Thursday and could figure in Saturday's opening pre-season friendly at Bognor Regis.
Maddox, who has represented his country at every level from under-16s to under-20s, began his career at Bristol City.
Need a VPN? Or seeking to switch? Then support Tribal Football by clicking here to sign up with our official partners NordVPN. Not only will you receive the best VPN experience, but also great discounts by signing up via Tribal Football. Thanks for your support!