Ruiz is expected to leave Napoli this summer, with the his relationship with the Serie A giants becoming increasingly strained.
Real Madrid are thought to be leading the race for the 23-year-old, while Barcelona are also keeping an eye on the former Betis man.
But according to reports in Spain (via the Daily Star) Liverpool are also interested in the versatile midfielder.
Fabian is valued at £74m by the report, but his agent admits he is unsure how much his client would fetch in the current market.
“There have been many changes in the club this season, it’s been a difficult year for Napoli,” Alvaro Torres told Marca.
“A renewal? We have set aside negotiations for a while, until the end of the season. There are very important clubs that have asked for information, and we have already informed Napoli.
“There is no release clause in his current contract. I really don’t know what Ruiz’s value is at present.”