Silva knows his winger needs confidence if he is to perform at his best and was quick to point out, he's barely featured over the past two seasons for various reasons.
"I know Carrillo very well. When he came here, he had a fantastic impact in our team," Silva told the Hertfordshire Mercury. "And in the Premier League – a lot of players and clubs don't know him.
"I know him well, he needs confidence and hasn't played many games in the past two years for a player of his quality. He had a fantastic impact, and in every moment he's started to grow."
Carrillo is currently on-loan from Benfica, though Silva says it's too soon to discuss a permanent deal.
"We'll see," he told the Watford Observer. "He's not our player, but I'm sure we will do everything we can to keep him.
"He needs to prove himself until the end of the season, and then we'll see what will happen."