The Belgian defender has done so well north of the border that his manager is already talking about trying to keep him another year.
Deila told the Scottish Herald: "I hope that we can build him up but also keep him for the Champions League, if we win the league and get into the Champions League next year, so that he can be an important player in that role as well. If we build someone up and then lose him it's hard to get that relationship back again.
"We have a very good co-operation with City, there are good bonds there. We talk well together. [Denayer] is very young still to be playing at this level and if we win the league and go into the Champions League it would be a perfect scenario for him because it is a very high level and he maybe needs a couple of years there. They are happy with what is happening here with him. I had a co-operation with City at Stromsgodset as well."
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