Ronny Deila is unlikely to remain at Celtic beyond the end of the season after their shock loss to rivals Rangers in the Scottish Cup semi-final, according to Pat Bonner.
An enthralling tie at Hampden Park on Sunday ended 2-2 after extra time, with Mark Warburton's Championship winners going through 5-4 on penalties to set up a final against Hibernian, also of the second tier.
Deila has overseen a frustrating season at Celtic despite sitting top of the Scottish Premiership. The club failed to qualify for the Champions League, crashed out of the Europa League group stages and also lost out at the last-four stage of the League Cup to Ross County.
Celtic and Republic of Ireland icon Bonner thinks it is difficult to see the Norwegian manager remaining in his role, even if he goes on to win a second straight league title, because winning the double should be seen as a minimum requirement.
"It is going to be difficult for him now," Bonner said to BBC Sport. "I have always said that a cup and the league would be the expectation this year.
"Now the cups are gone, the league is left - they will win the league no doubt. Will that be good enough to keep him in a job? I'm not so sure.
"It is a decision Peter Lawwell, Dermot Desmond and the board of directors will have to make now.
"They didn't have a good European campaign and they have played in bits and pieces. Maybe people put too much emphasis on Champions League, but for this club that is the target - to be in the group stages.
"It has been done in the past and that is what any manager should be judged on."
Bonner feels Rangers have progressed significantly under Warburton while Celtic have largely stood still under Deila, who is on a 12-month rolling contract.
He added: "I think Rangers have made dramatic strides compared to what we saw last year in this same type of fixture. They really have improved, there is no question about that.
"They play a good brand of football and the players look a lot more confident than they did. So, from that point of view, Celtic have not really progressed."
