The Reds signed Endo from Stuttgart last summer after they out to Chelsea in their bid to sign both Moises Caicedo and Romeo Lavia.
The Japan international made 44 appearances in his first season on Merseyside, chipping in with three goals and an assist.
Although he only joined Liverpool last year, it has now come to light that he has been the subject of a bid from Marseille.
Liverpool reject Marseille's Endo offer
According to journalist Fabrizio Romano, Liverpool recently turned down a €14m (£11.8m) proposal from the French giants.
The update states that Marseille's pursuit of Endo 'collapsed weeks ago' as they turned their attention to other midfield targets.
Roberto De Zerbi's side have since signed Canada international Ismael Kone from Watford for a €12m (£10.1m) fee, plus add-ons.
They have also recruited Pierre-Emile Hojbjerg on a season-long loan deal from Tottenham Hotspur, with an obligation to buy for a reported £17m.
Marseille are now focusing on strengthening in other positions, making it unlikely that will return with an improved bid for Endo.
Why did Liverpool reject Endo bid?
As per The Athletic, Liverpool turned down Marseille's proposal due to the timing of the offer and the lack of potential replacements.
The Merseyside club are not actively looking to sell Endo, with the midfielder under contract until the summer of 2027.
As it stands, Endo is one of Liverpool's main options to operate in the number six role, which also be filled by Alexis Mac Allister and Stefan Bajcetic.
Endo is currently involved in the pre-season tour of the USA, featuring in the first half of Friday's 1-0 win over Real Betis in Pittsburgh.
The 31-year-old will look to get more minutes under his belt when Arne Slot's side take on Arsenal in Wednesday's friendly against Arsenal in Philadelphia.
The Reds wrap up their tour of the United States with a meeting with rivals Manchester United on Saturday, before they return home for a clash against Spanish side Sevilla.