Celtic made a number of changes to their defence over the summer, in terms of personnel.
The Bhoys brought in the likes of Tyler Blackett, Dedryck Boyata and Jozo Simunovic during the summer transfer window, and Deila has yet to settle upon his first-choice back four.
The Norwegian boss says that the strength in depth that he possesses at the back is making his selection difficult, and it could be a while before the picture is cleared for him.
RD: It’s hard to say what's my best back-four because I haven’t seen enough of every player but I have eight or nine good defenders here.— Celtic Football Club (@celticfc) September 24, 2015
Celtic have had the tough job replacing a centre-back pairing which was the foundation for their success last season.
The partnership between Virgil Van Dijk and Jason Denayer played a key role in the double-winning exploits of 2014/15.
However, with Van Dijk joining Southampton and Denayer's loan at Parkhead expiring, the Scottish Premiership champions have been forced into transfer action to compensate for their losses.
At first, the new look Celtic defence made a shaky start, but the Bhoys have conceded twice in their last three games, and appear to be settling down as a collective.