LIVERPOOL, England — Liverpool signed left back Andy Robertson from Hull on Friday, filling a problematic position for the English Premier League team and continuing a stunning rise to prominence for the Scotland international.

The 23-year-old Robertson reportedly moved to Anfield for a fee that could rise to 10 million pounds ($13 million).

Liverpool manager Juergen Klopp played James Milner, a central midfielder, as a makeshift left back last season, preferring him to Alberto Moreno.

Just four years ago, Robertson was playing on a part-time basis for Queen's Park in the Scottish leagues and working in a supermarket. Next season, he'll be playing in the Champions League.

"For Andrew, this is another big step on what has been a quite incredible personal journey in a very short space of time," Klopp said. "I love his story, where he has come from professionally to reach this point."

Hull was relegated from the Premier League last season.

Also, Chelsea sent centre back Kurt Zouma on loan to Stoke for the whole of next season, after tying the France international to a new six-year deal.