Merse knows the Walker well from his time at Villa, for whom the 57 year old was a physio for fifteen years.
"Jim is on a course today and tomorrow, then he will see Jeff Bonser to sort everything out on Wednesday," said Merson. "He is not coming in as a coach, he is coming in as my assistant manager and I'm really pleased about it. He has been in the game all his life and his knowledge of it is excellent, plus he brings with him the fitness knowledge which will be a bonus. He is someone I respect and trust, which is important, the lads all respect him massively and he is a calming influence."
Merson and Walker will be joined by player coach Simon Osborn and another yet to be appointed coach who will aim to guide the Saddlers to the Coca Cola League One title this season.
Walker knows the Saddlers well, having worked at Bescot under Colin Lee as a part time fitness coach last season.