Hull and Ipswich are both looking to bolster their goalkeeper options this summer and are considering a move for Long.
Long, who has come through the ranks at Sheffield United, is down the pecking order at Bramall Lane and the summer signing of Dean Henderson on loan from Manchester United means his first-team opportunities look limited next season.
The 24-year-old spent last season on loan at League One AFC Wimbledon and he impressed during his time at the Dons, keeping 12 clean sheets in 49 games.
Hull are in the market for goalkeeping reinforcements this summer after seeing Allan McGregor leave at the end of last season on a free transfer back to Rangers.
Tigers boss Nigel Adkins is a big admirer of Long, having worked with him and made him his No.1 'keeper during his time in charge at Sheffield United, and he is keen to be reunited with the former England Under-19 international.
Ipswich are also considering their goalkeeping options in case they lose current No.1 Bartosz Bialkowski and Long is on their list of potential replacements.
Long has made 123 appearances for the Blades, but he has also had spells out on loan at Oxford United and Motherwell during his time at Bramall Lane.