Mamadou Sakho, Lazar Markovic, Sheyi Ojo and Cameron Brannagan are among the absentees from a 25-man Liverpool squad set to fly to Hong Kong on Sunday (16 July) to compete in the Premier League Asia Trophy, heightening speculation that all four players could be set to leave Anfield this summer.
Centre-back Sakho did not make a single first-team appearance for Liverpool in 2016-17 after being sent home early from a pre-season tour to the United States and was eventually loaned to Crystal Palace, where he impressed hugely during a productive eight-game stint that was curtailed by a knee injury.
The French defender began his rehabilitation in south London before returning to Melwood last month, where he has been training on his own in a bid to return to full fitness.
The Times subsequently reported that Sakho did not expect to be included in the travelling party for a six-day stint in the Far East after missing domestic pre-season friendlies against Tranmere Rovers and Wigan Athletic.
Following that opening 4-0 win over non-league opposition at Prenton Park, Klopp was quizzed as to whether Sakho might feature again for Liverpool with his hopes of securing a permanent move to Palace seemingly all but extinguished.
"First of all he needs to get 100% fit and then we will see," the manager responded.
Markovic looks certain to move on over the coming weeks despite appearing as a second-half substitute against Tranmere. The Serbian international has not played a competitive match for Liverpool since 2015, instead dispatched for successive loan stints with Fenerbahce, Sporting Lisbon and Hull City.
Winger Sheyi Ojo is the subject of loan interest from north-east rivals Newcastle United and Middlesbrough, while The Independent report that fellow youngster Brannagan is being tracked by Stoke City, Hull and Derby County with only 11 months left to run on his current contract.
It is said by the same publication that Liverpool will not sanction a temporary departure until he agrees an extension, something that will apparently not happen until he receives the necessary reassurances regarding a clear pathway through to the first team.
Pedro Chirivella and Connor Randall are also omitted from the squad for Hong Kong, although Ryan Kent makes the cut despite suggestions that he could join Hull on loan. New signings Mohamed Salah and Dominic Solanke are both included as expected, but influential forward Sadio Mane remains absent as he continues to recover from surgery to repair meniscus damage in his left knee.
Emre Can, who is believed to be close to signing a new deal on Merseyside, is still on holiday after helping Germany to Confederations Cup success in Russia. Nathaniel Clyne, Danny Ward and Alberto Moreno all travel despite missing the 1-1 draw against Wigan, although Danny Ings and Harry Wilson are yet to return. Georginio Wijnaldum picked up a minor head injury on Friday, but is fit for selection.
Lucas Leiva, meanwhile, is on the verge of joining Lazio in a £5m transfer.