"We needed strengthening in that area and the chairman has allowed me to do it.
"I know Asa has never played in the League but he has always played at a decent standard and he was on Stoke's books when he was younger.
"But a League career never materialised for him and he was probably a bit unlucky.
"Having said that a lot of these non-league lads who have a good job can earn decent money and have a good career at non-League level.
"We have offered him the chance and, at his age, he knew if he didn't do it now he may never do it. We are pleased to give him this opportunity and I think he will do well.
The left back has already been to Field Mill as Shirtliff looked at him earlier in pre season, and then again as the campaign got under way "He came up in the summer and again for a week's training and he has done well. I also have people in the midlands who have recommended him strongly."