Arsenal are tracking Sporting Gijon striker Carlos Castro.
O Jogo says Arsenal and Benfica are following the Segunda Division star leading up to the summer market.
The 19 year-old Spain U21 international has scored seven goals in 19 games this season.
Castro has spent his entire professional career with Gijon and is tied to the outfit until 2018.
He made his debut for Sporting B as a 16 year-old in 2012.