Former Northern Ireland manager Lawrie Sanchez has said the "writing is on the wall" for his successor Nigel Worthington.
Pressure on the current manager has increased following a defeat against Estonia that all but ends qualification hopes for Euro 2012.
Worthington has told the BBC he has no intention of stepping down.
But Sanchez said: "Nigel has had enough cracks at it. Everybody sees the writing is on the wall."
Sanchez, who is currently boss of League Two side Barnet, added: "He is not doing an exceptional job. It's not happening.
"It has got worse rather than better. Everybody realises it is time for a change."
Sanchez said he would consider managing Northern Ireland again should the Irish Football Association decide to sack Worthington.
"I have always said I would like to finish what I started," he told Radio Ulster. "I would like the opportunity. I would like to return to Northern Ireland in the future."
Northern Ireland lost 4-1 to Estonia in Tallinn on Tuesday.
The team now has effectively no hope of qualifying for the Euro 2012 finals in Poland and Ukraine - Northern Ireland last played in an international tournament at Mexico in 1986.
But Worthington said he has no intention of quitting.
"When I came into the job the press was saying 'you won't walk away from the job'," he said.
"My contract runs out on 31 December and until somebody says different, that's the situation. I would love to stay on."
Irish FA president Jim Shaw told the BBC on Wednesday that no contract negotiations would take place until the Euro 2012 qualifying campaign ends in mid-October.
Northern Ireland's performance was littered with individual errors.
Estonia were already 1-0 ahead when goalkeeper Lee Camp allowed Tarmo Vink's weak long-range effort to beat him.
An own goal gave Northern Ireland a lifeline at 2-1 but another mistake - this time by defender Gareth McAuley - gifted the Estonians a third goal.
Kaimar Saag added a fourth goal in stoppage time.
After a promising start to the qualifying campaign - including a draw with Italy at Windsor Park - Northern Ireland's challenge in Group C has faded dramatically.
Worthington has been Northern Ireland manager for four years. Following the game, he admitted mistakes were made.
"There is not a lot you can say, we contributed to our own downfall," he said. "We made errors and did not deal with situations the way we should have.
"It is hugely disappointing and a 4-1 scoreline is not nice to take. It was not our night but we have to take it and move on."