Cardiff-born Poole is a product of the Cardiff City and Newport County youth systems and, after breaking through to the Exiles first-team during the 2014/15 campaign, went on to join the Red Devils in September 2015.
Poole, who is also being tracked by Bradford City, made seventeen first-team appearances during just over a season in the County first-team and joined United for an initial fee of £100,000 and has since joined the youth and reserve ranks, chalking up several appearances.
Regan, who has made appearances for the Wales under-17, under-19, under-20, and under-21s, spent the whole of last season on loan with the Saddlers' then League One rivals Northampton Town, making twenty first-team appearances and gaining plenty of much-needed experience.
The Saddlers, who currently have Jon Guthrie as their only fit first-team central defender, are known to be on the look out for new signings with several players including former Liverpool and Middlesbrough defender Tom Brewitt and ex-Burton Albion centre-back Tomáš Egert being linked with a move to the Banks's.