The 21-year-old scored three goals in 18 appearances for Dean Smith's men, recently bagging a brace in the Bees' 2-2 draw with Cardiff City on Boxing Day.
Smith would have loved to have kept the Palace youngster but admits Brentford were powerless to prevent new Eagles boss Sam Allardyce from taking Kaikai back to Selhurst Park.
Smith told the club's website: "He is a player with great potential and he has made an impact for us, particularly in recent matches.
"This is his first taste of Championship football and he has made the step up, he is a player I have enjoyed working with. He is a Crystal Palace player and they have exercised their option to recall him.
"They have players going to the African Cup of Nations and have lots of games coming up so Sullay may be in line to play in the Premier League for them. They also have a new manager in Sam Allardyce and I am sure he wants to look at Sullay. I wish him all the best for the rest of this season and thank him for his efforts during his time here."