Castro has impressed for La Liga side Sporting Gijon this season.
A Bola reports that Benfica are in the market for a new winger and the club sees Castro as a good signing.
Valencia are also reportedly interested in the 28-year-old winger.
Castro has impressed for La Liga side Sporting Gijon this season.
A Bola reports that Benfica are in the market for a new winger and the club sees Castro as a good signing.
Valencia are also reportedly interested in the 28-year-old winger.
