Keita's younger brother, nicknamed Petit, is attending sessions at their club's Kirkby facilities.
He was previously been playing for Inter Leipzig, who currently play in the German fifth division.
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There is no suggestion that Petit is on trial with the club, or if he is close to joining Liverpool on a professional contract.
Image credit: Eurosport
First team manager Jurgen Klopp believes that Naby, currently out with a hamstring injury, is close to a return.
Klopp said: "Naby is in a good way already.
"He's outside running and all that stuff. So we'll have to see.
"We take it now day by day. We cannot put any pressure on that, we have to see when he is fully fit.
"It should not be that long anymore."
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