Seven points currently separate the three teams in the Premier League table, with Liverpool on 60, Tottenham on 58 and Chelsea 53.
The Newcastle United legend told the Premier League: "I fancy Liverpool in the four because anyone can get injured at any stage of the season, we know that.
"But if one of Mane, Salah or Firmino get injured, another can step up. Whereas if you look at Tottenham, if they lose Harry Kane, they haven't got anyone to replace him.
"I know there's [Fernando] Llorente but he's not in the same league as [Harry] Kane. If he were to get injured then you'd say Chelsea would miss out.
"So that's why I think Liverpool are firm favourites to take one of those Champions League because, if one of these guys get injured, then Firmino will step up or Mane will step up, and they can cover that."
All three clubs have nine league games left to play.