Since moving to Vicarage Road in May, Silva has brought in seven new faces, but it appears that he remains intent on making further additions before the end of the transfer window.
According to The Mirror, the Portuguese is keen to sign Carrillo, a player who he has previously worked with during his time at Sporting Lisbon.
The Peruvian international enjoyed an impressive five-year spell with Sporting, but the attacker made just three starts for Benfica last season, with a further 17 outings coming from the bench.
It has been suggested that if Watford are successful in tempting Benfica into a loan deal, the Premier League outfit would be obligated to complete a permanent switch next summer.
Watford began the season with a 3-3 draw with Liverpool last weekend.