Cadman, 24, was part of the Seadogs side that won promotion to the NPL Premier Division in 2017/18, but left last summer.
He went on to join Mickleover Sports, scoring a hat-trick in their FA Cup win over Coventry Sphinx.
Manager Darren Kelly said: "Cads is a great lad an a good footballer. He will be in a similar boat to Bailey Gooda, coming down for pre-season and then we'll take things from there."
Cadman started out at Rotherham United and has also featured for Stalybridge, Harrogate Town and Kelly’s former club Hyde.
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