The 22-year-old, who can also play on the left side of midfield, has helped the French side into the top half of the Ligue 1 table and earned his first cap for Portugal late in 2014.
Liverpool are expected to allow Jose Enrique, whose contract expires at the end of the season, to leave in January if a suitor can be found and are looking for a new left-sided defender to compete with Alberto Moreno.
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They have monitored Guerreiro's progress and the player is well known to Jurgen Klopp, who followed him when he was the manager of Borussia Dortmund.
"Raph has a contract [until 2017]," a source at Lorient told Goal. "We are very happy with him and he remains involved in the club project."
Liverpool are also lining up a move for Leicester full-back Ben Chilwell, who has impressed during a loan spell at Huddersfield Town and is a target of Arsenal and Tottenham's.
Lorient are set to lose Lamine Kone to Sunderland but Lamine Gassama, whom the Black Cats had also bid for, has turned down a move to the Stadium of Light.