Meanwhile, Casper has offered seven of his existing players new contracts and released half a dozen more following Bury's struggle to stay in League Two.
Alan Fettis, Tom Kennedy, John Fitzgerald, Matthew Tipton, Tom Youngs and Damian Quigley have been released, while Chris Brass has been invited back for pre-season to prove his fitness following surgery.
New contracts have been offered to Colin Woodthorpe, Nicky Adams, David Buchanan, Marc Pugh, Andy Warrington, Andy Parrish and Aaron Grundy.