Clark has dropped the Swansea City loanee after Blues first two games.
He said: "Kyle is going to be a massive player for us, a big, big player in this division. One of the best central defenders at this level.
"He's a big boy, he has got all the physical attributes. Technically he is very good.
"Kyle didn't play a lot of football last year. And we're just bringing him up to speed.
"He missed a couple of weeks in pre-season, which we need to get into him as well.
"But I said to Kyle last week when I left him out that he is still going to be one of the main central defenders in the Championship this year."
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