IN hindsight, the seeds of Saturday night's dramatic dismissal were sown at Loftus Road. Long after everyone else had left the directors' box in the wake of Sunderland's 3-1 defeat to QPR earlier this month, Ellis Short remained slumped in his seat with his feet propped up on the row of chairs in front of him.

Furious at his side's tame surrender against a team that had kicked off at the foot of the Premier League table, Sunderland's American owner appeared to be confronting the enormity of the train wreck that was approaching if Martin O'Neill was unable to guide his players to safety in the final two months of the season.

In a brief chat in the hour or so after the game, he railed at the inadequacies of Sunderland's performance and outlined a determination to oversee the changes that were required to turn the club around.

At that stage, there was no indication of a threat to O'Neill's position – in conversations with other observers, Short spoke of a need to “protect” his manager – but there was anger at the mess Sunderland were embroiled in, frustration at the millions that had been pumped into the club in an unsuccessful attempt to engineer improvement and an acceptance that relegation was something that would have to be avoided at all costs.

Two games on, neither of which Short has attended in person, and the blame for the unfolding shambles has been laid firmly at O'Neill's door. Had the Northern Irishman remained at the helm, Short has clearly concluded that Sunderland would have been destined for the Championship, and as this month's financial results make clear, that would have been disastrous.

The club lost £27m in the last financial year. Factor in a £20m reduction in income that would be an inevitable result of relegation, and you're left with a near £50m black hole. Short, who built his fortune working for a private equity firm in Texas, boasts an estimated wealth of around £1bn. Even so, the sums have proved too unpalatable to stomach.

Well used to high-stake gambles thanks to his links with hedge funds, the London-based American has decided that the risks associated with dismissing O'Neill are preferable to the dangers that would have gone hand-in-hand with doing nothing.

Watching Sunderland's tame surrender at the hands of Manchester United at the weekend, it felt as though the club was sleepwalking towards relegation. It is not any longer, and Short's willingness to explore every avenue in an attempt to stave off the drop is to be applauded.

This is not a decision he has taken lightly, nor is it the easiest or cheapest option available to him. Yet it still feels as though it is a last desperate roll of the dice that is more likely to fail than succeed.

With seven games to go, this is surely not the time to be sacking your manager. When Paolo Di Canio begins his first day in charge of the Black Cats this morning, he will inherit a squad with extremely limited scope for alteration.

Look at the players on the substitutes' bench at the weekend – Keiren Westwood, Matt Kilgallon, Kader Mangane, Seb Larsson, Jack Colback, Connor Wickham, Mikael Mandron. Are any of those going to force their way into the first team to transform Sunderland's season?

With Steven Fletcher and Lee Cattermole unable to play again this term, the players who lost to Manchester United are the players who are going to have to turn things around. There is scope for some minor tactical tinkering – perhaps Wickham and Danny Graham could play as a front two? - but there will be no wholesale transformation in the last seven games.

So the only real hope is that Di Canio will come in and change the mood at the Academy of Light training ground, instilling confidence and passion into a squad that currently appears to possess neither.

It could happen, O'Neill himself had an instant impact in terms of transforming morale, but the fixture list hardly plays into Di Canio's hands.

On Sunday, Sunderland travel to Chelsea. Morale boost or no morale boost, it's hard to see the Black Cats taking anything there. Next up after that? St James' Park, and a Tyne-Wear derby that is arguably as big as any meeting between the two great North-East rivals in the last 20 years.

Win that, and Sunderland's season truly will be transformed. Lose it, though, and Di Canio's reign will be as good as over in the eyes of the supporters before it has begun.

If Short was going to act, should he not have done it in the immediate aftermath of the QPR defeat? By delaying, all he has done is deprive Di Canio of the opportunity to kick off his reign with an imminently winnable home game against Norwich City and another, admittedly difficult, home outing against Manchester United.

Instead, three of the new manager's first four games will be away from home, and Sunderland have not won on their travels since they edged out Wigan in mid-January.

In this part of the world, there are two precedents for this kind of decision. The first ended positively, with Peter Reid replacing Mick Buxton in March 1995 before leading Sunderland to First Division safety in the final seven games of the season.

The second, however, was a disaster, with Alan Shearer taking charge of the final eight games as Newcastle crashed into the Championship in 2009.

Time will tell whether Short's dismissal of O'Neill is a master stroke or disaster. Either way, though, it is surely a move that will come to define his ownership of the club.