Liverpool continue to be heavily linked with Udinese's Piotr Zielinski and Borussia Monchengladbach's Mahmoud Dahoud and it is understood that Klopp is prepared to part ways with Brazilian Leiva and Wales star Allen.
29-year-old Leiva has indicated that his future at Anfield is clouded but insist he will report for pre-season training to discover more about Klopp's plans going forward.
"There have been some changes last season, with the coaching change," he told Radio Joven Pan.
"I still do not know what exactly will be my role within the group, but I am returning (to England) on Thursday to start the pre-season.
"It is the first transfer window in which Klopp will participate more actively in Liverpool, so I'll just get a better idea when I return.
"Whatever happens, the idea, as always, is to stay in Europe, especially in England, which has a very strong and good league to play."