Dasilva suffered major ligament damage to his right knee in training earlier this month and had only just returned from a hamstring injury he sustained in August.
It remains to be seen whether he will play again this season, and his future is also uncertain with his contract due to expire this summer and the club yet to decide whether to offer him an extension.
The 25-year-old missed 12 months between February 2021 and February 2022 with a hip injury.
Dasilva took to X, formerly Twitter, saying: “Disappointed to have suffered such an injury, I’ve come back before so I know I’ll come back even stronger. Appreciate all the love and support shown from the past week. See you soon.”
Brentford manager Thomas Frank said last Thursday: “In training [he had] an unlucky action, unfortunately. Let’s get surgery out the way, but I don’t want to put a timeframe on it. That is a long-term one.
“Very sad, I feel for Josh massively. He’s been very unlucky. It’s a player I’ve been working with for a long time. Normally over time your relationship grows, and he’s a lovely person, so that was tough to take.
“Last year he had a season where I think he was available for every single game. Maybe the head coach didn’t give him enough chances, but he did well for us.”
Frank added: “I thought he had a big season ahead of him [this term], but he was very unlucky with a hamstring injury in our second game against Fulham. And then this knee injury. I spoke to him on the day of the injury. The next period we need to give him all the support we can.”
Frank said about the possibility of a new contract: “He needs to go through the surgery first so we get a clear picture of that.
“Of course, we would like to look after players and do what we can to help them in the future. We will take a decision on that after the surgery.”