Arsenal are keeping tabs on Portugal midfielder Danilo, reports A Bola.
The 25-year-old, who joined Porto from Maritimo in 2015, is being monitored closely by the Gunners.
Danilo is contracted to Porto until 2020 and has a €40m buyout clause.
Danilo featured five times for Portugal during their triumph at Euro 2016.
The Guinea-Bissau-born enforcer has fought his way back to the top of the Portuguese game after being released by Benfica in 2010.
He spent time at Greek club Aris Thessaloniki and Dutch side Roda JC before moving to Maritimo.