Arsenal scouts were in Portugal over the weekend to run the rule over Sporting Lisbon's William Carvalho, reports Portuguese source A Bola.
The 21-year-old has impressed for Sporting Lisbon so far this season, breaking in to the first team following a successful season on loan to Cercle Brugge last year.
His fine form has attracted the interest of Arsene Wenger, who sent his chief Spanish and Portuguese scout Francis Cagigao to evaluate Carvalho's potential in the game against Nacional.
Cagigao is famed amongst Arsenal fans for recommending Cesc Fabregas to Wenger while he was still playing for Barcelona's youth academy.
Fabregas went on to captain Arsenal at the youthful age of 21 before rejoining the Nou Camp outfit.
But Arsenal aren't the only Premier League team thought to be interested in the midfielder.
Manchester United have reportedly sent scouts to watch Carvalho six times as David Moyes looks to strengthen the midfield at Old Trafford in January.
Carvalho is believed to have a €45m (£37.5m) release clause inserted in to his contract but Sporting Lisbon will sell for £20m.
But, according to A Bola, Arsenal weren't just looking at Carvalho.
Cagigao was also watching goalkeeper Rui Patricio, who Arsenal reportedly made a €10m bid in the summer.
Wojciech Szczesny has become a firm number one at the Emirates this season but Lukas Fabianski is believed to be on his way out of north London while Emiliano Viviano is only on a season-long loan spell, increasing the need for back-up.