The 25-year-old, who spent almost eight months on loan at St. Andrew’s from Swindon Town last season, was only made aware of the move yesterday morning.
“It's good that the club have come up trumps and got the money together because I know how hard it is behind the scenes,” said Caddis.
“Yesterday the (Swindon) owner called me over ten minutes into training and said that a bid had been accepted from Birmingham, so from pretty much half past ten in the morning I was on the go saying my goodbyes to the people at Swindon. I was there for four years and I've got a lot of good memories, but when one window closes another one opens.”
The Scottish full-back is looking forward to working with some familiar faces.
“I always had an idea that I could come back here,” he said. “I was happy and enjoyed it. I have a good relationship with the manager and ultimately this is where I wanted to be.
“I know what the manager wants from me and he knows what I give him. I already knew last year that he planned to build a young team and that's something I bought into and want to be involved in.
“There are also a lot of familiar faces which always helps when you come back to a club – people like Robbo, Darren Ambrose and Burkey that I got quite close to last year.”
“I'm just quite glad that it's on a permanent rather than a loan because I can get settled into a club of this size and hopefully onwards and upwards for everybody,” Caddis concluded.
“I'm not going to promise fans that I'm going to be a 30-goal a season player or provide three or four assists every game, but I can assure them of one thing and that’s that I'll give 100 per cent every game.”
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