Manchester United and Stoke City had scouts posted to Portugal on the weekend.
Record says representatives from United and Stoke were present to see Pacos de Ferreira host Sporting CP.
AS Monaco, Lille, Espanyol and Celta Vigo also had scouts in attendance.
The match finished 1-1, with Islam Slimani's opener being canceled out by Rodrigo Galo for Pacos de Ferreira.