Speaking to the Mansfield CHAD, Shirtliff said of his decision not to renew Sheehan's loan deal for another month "Alan has been good for us and I think we've been good for him.
"But we have sent him back as he is out with an infected toe and can't play in the Cup on Saturday anyway.
"There are only three games he could play in during November so it's not really worth using that last month up. But, depending on how things work out, we could maybe bring him back to cover us through December for his third month like Lincoln have done with Forest's Nicky Eaden."
Redditch United left back Asa Charlton is now Shirtliff's target, as he is now revealed that a deal to land the 28 year old for the remainder of the season is now on the table.
Charlton will be unavailable for the FA Cup tie with Accrington Stanley, as he is cup tied.