Liverpool won the league by 18 points last season but have already failed to win seven matches this term to give their rivals hope of dethroning them as champions.
Jurgen Klopp’s side are currently top but Man United will join the Reds on 33 points if they beat Aston Villa on Friday night.
Everton, Leicester City, Villa, Chelsea, Tottenham and Man City are all within touching distance of Liverpool.
Asked who he believes will win the Premier League this season, Cascarino told The Times: ‘I’ve said all along it’s between Liverpool and the two Manchester clubs and I stick by that.
‘Manchester City’s defensive solidity making them the favourites. The winning points tally might be very low.’
The former Chelsea and Ireland striker added: ‘We’ve seen Arsenal and Southampton stick by their manager in recent times despite poor results and I think Manchester United were right to do the same.
‘You can’t expect a quick fix. Solskjaer should only be judged at the end of this season.’
Former striker Louis Saha, meanwhile, believes there are five teams who can win the title this season.
Saha, speaking exclusively to Ladbrokes at its launch of the 5-A-Side Bet on Tottenham v Fulham, said: ‘Liverpool are definitely the ones to beat for the Premier League title this year.
‘Jurgen Klopp has such a great group of players who are eager to win every single game.
‘It’s a lot more difficult for Man City this season because in terms of creating chances, it feels very much like Kevin De Bruyne is on his own now since David Silva left the club.
‘There’s now less guarantee in that Man City side winning games and ultimately the title than there is in Liverpool.
‘I’d probably say there are four or five teams in with a genuine chance of winning the title.
‘I’d definitely put Man United in there, Tottenham in there for sure as well. Chelsea have a good chance too, as well as the obvious two.
‘I’m actually loving the competitiveness of the Premier League this season. Football needs it.
‘When you look at leagues like Spain and France where it is always the same one or two teams – it’s great to see such a wide-open league in England.’