The Norwegian will leave the Scottish Premiership side at the end of the season.
The Norwegian is set to leave Parkhead at the end of the season despite winning the Scottish Premiership in both of his campaigns with the Hoops.
Deila's failure to add to the league titles and League Cup trophy he won last season, as well as their failure to go on any kind of European run appears to have played a significant role in the decision for him to step down.
And Lawwell has somewhat confirmed that theory by suggesting that being knocked out in the play-off round of this season's Champions League was the moment when the writing started to be put on the wall.
"We played really well towards the end of last season. So we felt pretty confident," he told The Scottish Sun.
"Then Malmo came - and bang!
"That was the turning point. The pressure started to mount on the back of that.
"Supporters were disappointed, we were disappointed, pressure came from the media and from that point it was difficult for Ronny to recover."
While few Celtic fans expect the club to repeat the heroics of the Lisbon Lion in 1967, they rightfully expect to be competing in the group stage at the very least, especially as it provides the level of competition that the top flight does not.
Unfortunately, Deila has been unable to oversee any of the famous European nights that Celtic Park has become synonymous with down the years. And the fact that it was confirmed that that would be the case so early this term, against a side they arguably should have beaten, meant that he was always going to struggle to win the fans back round.