The right-back joined Blues on a season-long loan from Swindon on August's deadline-day, and duly impressed in his first three games for the club only to dislocate his shoulder in late September and spend two months on the sidelines.
Caddis was back in full training last Friday and made an earlier than expected return to the field for Tuesday's 1-1 draw at Blackpool, where he picked up exactly where he left off.
"What a player," raved boss Clark.
"Ten weeks out, two days training with the group. He's had four games for Birmingham City Football Club - I think he's been man of the match in every one.
"He's been outstanding. I love it because I know young players and the lower leagues where I've come from and there's some right good players who are desperate to get to this level and the level above.
"They'll work and they'll fight and they'll give everything but they've got the quality as well. These type of players are where I see the foresight to go forward with the football club, how I want to do it. His performances just back up what I say about that situation."