Liverpool have been in negotiations with Roma about Mohamed Salah but fear being priced out of a move for the Egypt international, and PA Sport reports that Martins -- linked with Real Madrid and Barcelona last season -- is seen as a potential option.

It has been claimed in Portugal that Martins has a buyout clause of €60 million (£52m) but that Sporting's failure to qualify for the Champions League means they would take €50m (£43.5m).

The 22-year-old made 44 appearances last season, scoring seven goals and providing 14 assists, and produced a particularly impressive individual performance against Madrid at the Bernabeu in the Champions League in September.

Liverpool boss Jurgen Klopp has said he wanted to add an attacking winger in January, and sources told ESPN FC last week that the club was also monitoring Keita Balde at Lazio and PA Sport reports that Bayern Munich's Douglas Costa is also under consideration.

It is reported that Roma's valuation of Salah is far in excess of Liverpool's, who had a £28m bid rejected last week, and the Serie A club are asking for more than the €40m (£35m) being reported in Italy.

Roma's American chairman James Palotta told US radio station SiriusXM: "For the moment, there is nothing with Liverpool. We'll see what to do."

Klopp is keen to significantly strengthen his squad this summer in preparation for Champions League football and has been linked with a move for Southampton centre-back Virgil van Dijk.

Sources told ESPN FC that the Netherlands international has made Anfield his preferred destination, should he leave St Mary's, although Saints have asked the Premier League to investigate an alleged illegal approach from Liverpool for the player.