The 18-year-old had passed a medical with the Trotters after the clubs agreed a fee but then surprisingly snubbed the offer from fellow Scot Dougie Freedman as he was not prepared to leave home.
"I was really shocked to be honest," said Reid, quoted in the Daily Record.
"As far as I was aware the move was pretty much done and dusted. The clubs had agreed a fee and we'd moved on.
"I wasn't privy to the discussions about the fee involved but I was pretty certain he'd be away. But Gary decided he didn't feel the move was right for him.
"He didn't feel he was ready to leave his family and a local environment at such a young age. It was a big opportunity for him but he's made his call.
"Gary will have to now work hard here at Accies and hopefully he'll do that and kick on. He has made about 10 appearances for us and it's up to him now to break into the side permanently.
"He's a talented boy. It's not for me to say whether he'll get another chance again. Gary just needs to get his head down and work on his game."