Watford signed the 20-year-old from Brazilian side Fluminese earlir this summer and despite his tender years, the youngster has been a key part of Watford's impressive start to the new season.
Richarlison has scored two goals in six Premier League games so far this campaign and Sila believes that the youngster can go as far as he wants to in the game.
Speaking ahead of Saturday's game against West Brom at the Hawthorns, Silva told the press: "He's a player we identified and analysed in June in Brazil and many times we watched him, we analysed him really well.
"I spoke to our board to see what we could do to buy the player. Of course he's not a cheap player but I said we had to buy this player.
"When I knew the player was ready to travel to sign with Ajax I did everything to stop that happening.
"I believe in the player and I believe he will help us. We need to be calm with him because he is 20 years old but he is a player who everything can happen in his career.
"We aren't putting pressure on him, we just want him to continue showing what he has done so far and keep working hard."