The 21-year-old has signed a two-year deal at Aggborough Stadium following his release by the Saddlers in May this year.
He made just two appearances for Walsall and also played for both Bromsgrove Rovers and Willenhall.
"It was a big drop from Walsall to the level I was at last season but it's improved my game a lot and made me much stronger," Coleman told the club's official website.
"It's a step-back up again and now it's time to knuckle down and work hard, I'm already settling in well and there's a good group of lads here and hopefully I can learn things from them and Scott Bevan.
"I want to get involved as soon as I can and as much as I can."
Source: http://www.confguide.com/newsArticle.do?id=6761