The Reds have made an indifferent start to the season, winning eight of their 16 games in all competitions.
Suarez, who scored 31 league goals last season, joined Barcelona in a £75m deal from Liverpool in July.
And former Liverpool striker Heskey reckons the Reds will need some time to adjust to all the new faces at Anfield.
“Replacing Luis Suarez – you are looking at probably the third best player in the world,” Heskey told BBC Sport.
“It will be difficult. Brendan Rodgers has brought in players who have not adjusted to the Premier League. It will take them a year to adjust.”
Heskey scored 39 goals in 150 Premier League appearances during a four-and-a-half year stay at Anfield.
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