One player who is unlikely to be lining up for Liverpool for their Premier League opener against Arsenal on August 14 is defender Mamadou Sakho, who underwent treatment for a long-standing Achilles problem.
The France international has not played since April after being informed by European football's governing body that he had failed a dope test.
UEFA dismissed the case against the 26-year-old last week, but Sakho missed Liverpool's Europa League final defeat by Sevilla in May and was dropped from France's squad for the European Championship as a result of the charge.
"Mama is injured. He had a little issue with his Achilles when he was playing, one day on, one off, this kind of thing," Klopp said.
"When he had his little 'break' he used the time to have a little bit of treatment and that now means another three or four weeks before he can train again."
Klopp did not want to get drawn into whether the matter was now closed.
"I cannot say too much as a manager," Klopp added. "I don't know exactly what will happen now from Mama's side or UEFA's side.
"Others have to talk about this because I don't know what I am allowed or able to say."
Image: Mamadou Sakho
Photograph: Cathal McNaughton/File PhotoLivepic