The 56-year-old boss believes the booking picked up by the Bulgarian was a needless one and has promised to have a private word with the player over his future conduct in games
The Cottagers are currently on a run which has seen them claim just one victory in their last 11 games, sliding down the table into 14th position as a result and picking up just five points out of a possible 21 recently.
With Berbatov grabbing the first goal against Nigel Adkins' fellow strugglers, the 31-year-old forward was cautioned for taking his shirt off and revealing a T-shirt which read the message: 'Keep calm and pass me the ball', a move which both puzzled and angered Jol.
"It was a bit stupid and I will have to have a word with him," Jol said.
|FINDING THEIR FORM AGAIN|
|7/1||Fulham are 7/1 with Paddy Power to beat Swansea 2-1 at Craven Cottage|
"He probably thought he would get away with it as he never gets booked. It wasn't the brightest thing to do but he wanted to make a statement.
"He tells the youngsters every day to play with confidence, keep the ball and don't be afraid. You need confidence and self-belief to play your football.
"He wants us to play in a certain style and that is the message he's trying to get across."
Fulham host Michael Laudrup's in-form Swansea side at Craven Cottage next up on December 29, looking to turn their fortunes around.