Kieran Tierney is a very promising young defender who has been on the books of Celtic his entire professional career so far.
The 18-year-old has already made his first-team debut for the Bhoys, and Deila needs to give him more chances as the season progresses.
Of course, with Celtic playing catch-up in the Scottish Premiership at the moment, it may not be possible for the Norwegian to play the teenager right away, but he should hand him first-team experience in the coming months, perhaps as a substitute.
Celic signed Tyler Blackett on a season-long loan deal from Manchester United in the summer transfer window.
The 21-year-old is a versatile defender who can play as a left-back or as a centre-back, and he must be given more chances in the coming weeks.
Unless Blackett is allowed playing time, he will not be able to show what he is capable of. Instead of playing the error-prone Efe Ambrose in central defence, Deila could make use of the youngster in that position.