West Ham had a scout in attendance at Porto’s game against Portimonense at the weekend, according to reports in Portugal.
Moussa Marega, Hector Herrera and Yacine Brahimi have all been previously linked with a move to the Hammers, and it is assumed that representatives were keeping an eye on the trio.
All three got on the scoresheet in the 3-0 win over Portimonense so they would have all clearly impressed the visiting scouts.
Both Herrera and Brahimi are available on free transfers in the summer when their contracts expire so those two would be the most likely signings.
However, Herrera has been heavily linked with a move to Atletico Madrid so the prospect of the Mexican arriving at the London Stadium is quite low.
Marega would be even less likely with the Mali captain having recently extended his contract until 2021 with his release clause reportedly in the region of €40m (£34.5m).