Porto pair Vitinha and Evanilson are being watched by Manchester United.
United had scouts posted to check on Porto's Champions League defeat to Lyon in midweek.
Subject of their interest was OL striker Moussa Dembele, though O Jogo says Vitinha and Evanilson will also have been on their radar.
Midfielder Vitinha had a spell on-loan with Wolves last season and has seen his form and profile explode this season.
Brazilian striker Evanilson, meanwhile, is Porto's top scorer this campaign and has seen his asking price doubled to €20m.