"You are probably going to need 40 points minimum whereas three months ago you would probably have snapped anyone's hand off for 36 points," he says.
"The way things are going I think 40 points is going to be needed - at least - and if we keep getting the points, someone will get dragged into it that we will overtake."
He says the situation has changed from the start of the year, and adds:
"I think to be honest it looked like it would have to be three from the bottom four and there was three points where we all kept losing, with each as bad as the others.
"Now Sunderland and West Brom are nine and 11 points behind West Ham and 11 and 13 points behind Bolton, so really it is the form of us and Bolton that has really stretched the gap with those two, when you think how long we were together.
"Leeds are probably playing as poor as anyone and are looking anxious; they have a new manager but it is not that easy to turn it around when confidence is so low - as we know ourselves.
"Birmingham are on 35 points, Robbie Savage is suspended for the next couple of games and Clinton Morrison is out for the rest of the season, but they have done well in matches at Villa, and beating West Brom and Liverpool, giving them nine points - which has made a huge difference.
"I think Aston Villa, although they are on 36 points, have it as tough as it gets with games at home to Arsenal, away to West Ham and then over Easter at home to Chelsea and away to Newcastle.
"You have to look at West Ham needing to win that as it is one of three home games left, and then Villa have to pick up points from Arsenal Chelsea and Newcastle and if not they would definitely come into it then.
"So there is plenty of incentive to aim for."
Trevor was pleased with the recent point at Goodison Park and adds:
"I think the Everton one was important because in the run-in that game looked as tough as any fixture, and you have got to be able to do it away from home.
"So to have that clean sheet at Everton, who have been excellent at home was a big boost, and then the game against Sunderland where everyone was expecting West Ham to win was crucial, because we all know it is not that simple.
"With three wins and a draw, and seven games remaining, it gives everyone a terrific incentive, with Bolton going well themselves, to drag three others into it - with Leeds, Birmingham and Aston Villa looking over their shoulder.
"I have always said you have got to be getting the results yourself; yes, you put pressure on other people but more than anything you get the momentum.
"I think, to be fair, Bolton deserved the win against Spurs recently although it came in the last minute, and Okacha, who is very much a character, tucked the penalty away.
"Birmingham were more fortunate because it was the 94th minute when they scored and it was a dour derby that saw a lucky deflection spiral the ball to the far post for Horsfield to head it in.
"But once you get over the initial disappointment of those two sides picking up more than they might have done I think you still have to look at yourselves as the priority - and if West Ham keep picking up points in the remaining matches, then that is the main thing."
* Michael Carrick will have a scan on his groin problem sustained while on England U21 duty on Tuesday.