Real Betis' young star has gained plenty of attention of late.
The 21-year-old has shone since becoming a more regular figure in La Liga.
Fabian spent the second half of last season on loan at Elche in the Segunda Division.
Since returning to Betis, he started last month's 1-0 win at the Bernabeu and also put in a Man of the Match display in a 4-0 thrashing of Levante.
The attacking midfielder has three assists and one goal in his past two La Liga matches.
And according to Spanish outlet Don Balon, Fabian is on Madrid's radar.
Real president Florentino Perez has a good record of signing rising talents such as Matin Odegaard and Marco Asensio.
Fabian is now on his agenda to help shore up Madrid's midfield options for the future.
However, the Spain Under-21 international also has admirers from the Premier League.
Don Balon add United, Arsenal and City are all tracking Fabian.
The English trio, along with Madrid, would apparently be willing to sign the Betis ace for a bargain price.
Spanish journalist Eduardo Inda said on TV show El Chiringuito that Fabian has a buy-out clause of £13.4m.
Having risen through the ranks at the La Liga club, Betis now face a battle to keep hold of Fabian.
