Manchester City are understood to have held an interest in Ruiz for a while and could be considering a summer bid.
However, according to the Express, Real Madrid sent scouts to watch the midfielder in action for Napoli on Friday.
City are on the hunt for a replacement for their long-serving playmaker David Silva, who turned 34 in January.
The Spaniard could be succeeded by his countryman Ruiz if the reigning Premier League champions can agree a deal with Napoli.
It's clear that the interested pair will have to dig deep into their pockets if they are to convince Napoli to sell.
"I paid €30m for Fabian and he’s a fantastic player," De Laurentiis said.
"If some of the European top clubs were to offer €180m (£150) we can start talking about selling him."
However, it's reported that a bid closer to the £80m may be enough to force Napoli's hand.
Real Madrid do have one significant advantage over City in that they're likely to offer Champions League football next season.
