The Reds are currently top of the table and two points clear of Chelsea with five games remaining in the campaign.
It’s going to get much harder to win the Premier League after this season
Liverpool face third-placed Manchester City, who have played two games less than the Reds, at Anfield on Sunday.
And Whelan, who won six English championships during a decorated Liverpool career, underlined the importance of ending their 24-year wait this term.
“I think this is the best chance Liverpool will have for a long time,” Whelan told Sky Sports.
“They’ve already qualified for the Champions League – that’s pretty much a given – but that means they’re looking at a lot more games next season.
“They don’t have the squad to take them through the Premier League, Champions League, FA Cup and League Cup. They will need to add more players, but it’s going to get much harder to win the Premier League after this season.”
Whelan has been impressed with Steven Gerrard’s performances in a deep-lying midfield role in recent months.
“Steven is now playing in front of the back four, rather than running wherever he wanted to run,” added Whelan.
“That was in his DNA, he always wanted to get forward. Now he knows the job. You sit in there, cover for your full-backs if they go forward or if your centre-back steps out of the line, and I think he’s done that brilliantly.”
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