Hull City, Newcastle and Sunderland are the teams still at risk of filling the final relegation spot.
On paper, Hull have the most difficult task because they play a Manchester United side still fighting for third place, the automatic qualifying spot for the Champions League.
Sunderland have two bites at the cherry but have equally tough fixtures against Arsenal and champions Chelsea.
The permutations are that if Hull fail to beat Manchester United, they are down regardless of other results.
If they do secure an unlikely win over Louis van Gaal's Red Devils, they will also need favours from Sunderland's opponents Arsenal and Chelsea as well as West Ham at St James Park.
If Hull win and Newcastle don't, the Tigers will send the Magpies down thanks to a superior goal difference. However, if Hull and Newcastle both win and Sunderland lose to both Arsenal and Chelsea, then it will be Dick Advocaat's men who tumble down into the Championship.
Allardyce has the incentive of sending the club that discarded him back in 2008 down.
However, the potential for West Ham United to get into the Europa League via the FIFA Fair Play standings - the Hammers are currently the highest placed team in the Fair Play table not to have qualified for Europe through league position - could make a mockery of relegation D-Day.
That's because as much as the Hammers and their former Newcastle manager Allardyce might deny it, their players will be wary of competing too strenuously as any bookings or flare-ups would impact their backdoor route into Europe.
The Fair Play system may be deemed far from fair by Hull boss Steve Bruce and Advocaat come 5pm on Saturday.
They would have a point too, the system is being abolished next season in favour of one financial prizes to the fairest clubs.
But John Carver won't care as long as his boyhood club are still in the Premier League come the summer.
And he is leaving nothing to chance by reiterating just how big the game is for the Magpies.
"It’s a do or die situation," he said.
“We shot ourselves in the foot here, but this is now the biggest game this football club has had for a long, long time. One of the biggest in the club’s history."