Whelan thinks that the Merseyside outfit, who have not been champions of England since 1990, could struggle to compete with the likes of Manchester City and Chelsea next term due to their squad being stretched by their return to the Champions League.
"I think this is the best chance Liverpool will have for a long time," Whelan, who won six league titles during his time at Anfield, told reporters.
"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."