The Brazilian international has been a key part of the club’s success over recent years, forging an excellent understanding with fellow attackers Sadio Mane and Mo Salah.
But Firmino, who has two years left on his contract, turns 30 in October and his goalscoring output has steadily declined over the last four seasons.
He registered just nine goals in 48 appearances last season, with Salah the only one of Liverpool’s famous front three to maintain his usual high standards.
According to The Express, Jurgen Klopp has identified Isak, who has a £60million release clause, as a potential successor to Firmino after a series of excellent performances in La Liga.
The young Swedish striker boasts a potent mix of height, strength, speed and skill, which has seen him likened to compatriot Zlatan Ibrahimovic.
He made his breakthrough with boyhood club AIK at 16, beating the record for youngest scorer in Allsvenskan history on his debut.
Although opportunities were few and far between in the Bundesliga, Isak enjoyed an impressive loan spell at Willem II, which convinced Real Sociedad to bring him in on a five-year contract.
He scored 16 goals in all competitions in his debut season as Sociedad finished sixth and won the Copa del Rey.
The 21-year-old found the net 17 times in 34 La Liga games last season, including a hat-trick against Deportivo Alaves in February.
Some of Europe’s biggest clubs are monitoring Isak’s progress at the Euros this summer, where he was a continued threat to the Spanish defence in Sweden’s opening game.
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