His mentor is none other than McGrain, the Celtic reserve team coach who at just a couple of inches taller than Caddis was arguably the finest right-back Scotland has ever produced.
"I work with Danny a lot and he's great for me," said Caddis. "I've watched videos of him playing and it's true what they say, he was one of the greatest full-backs of all time.
"I look at someone like Danny, and more recently to another great Celtic right-back Jackie McNamara who also wasn't the biggest, and I know that my height isn't going to stop me making it here.
"I know there are other players on their way back from injury, but the gaffer put me in and I showed him what I can do. I want to make it as hard for him as possible."
