The Premier League club’s search for a new boss has taken on fresh urgency after Sunday’s 4-1 loss at Southampton.
Allardyce, 63, was an early candidate to succeed Ronald Koeman, who was sacked on October 23, but withdrew after Everton delayed making an offer.
The Toffees, whose pursuit of Watford manager Marco Silva has reached a dead end, have lost five of the seven games they have played since Koeman left.
Allardyce has been out of football since leaving Crystal Palace at the end of last season.
He saved Palace from relegation, having left the England job in September 2016 after just one match in charge.
Dutchman Koeman was sacked by Everton after the club slipped to 18th in the Premier League following a 5-2 home defeat by Arsenal.
David Unsworth – the club’s under-23s manager, who had two spells at Goodison Park as a defender – has been in caretaker charge.
He has lifted Everton to 16th, collecting four points from his four league matches.
The need for major shareholder, Farhad Moshiri and chairman, Bill Kenwright to appoint a manager has become more desperate after a 5-1 home defeat by Atalanta in the Europa League on Thursday and Sunday’s thrashing at St Mary’s.
Everton spent more than £140 million the summer but failed to replace top scorer Romelu Lukaku after his move to Manchester United.
They are two points above the relegation places and third-from-bottom West Ham United, who they face at Goodison Park on Wednesday.
David Unsworth admits that it hurts to see Everton losing
It took Sam Allardyce time at Crystal Palace to get it together. But you would expect him to get Everton safe.
Everton need to stop conceding goals first and foremost. That’s why they have gone to Sam because they are conceding goals. He is the best candidate for that.
He is the kind of manager Wayne Rooney will respond to. He would utilise him to the best of his ability because he is someone he will respect.
The fans might not be massively excited – and I don’t mean that disrespectfully to Sam. If Marco Silva was coming in, they might feel a tad more excited.
With Sam, the players will get a very clear impression of the way forward. It will be ‘you do what I tell you. it’s as simple as that’.
Sam is very good at organising in a crisis situation and because he makes his own points loud and clear.
If Sam gets the job he will load that team with experienced players – with his big hitters.
BBC