Fabregas was sent off as Chelsea lost their opening Premier League game 3-2 at home to Burnley.
The ex-Arsenal star struggled to impose himself on the game and angered manager Antonio Conte by becoming the second Chelsea player to see red on Saturday.
And Conte can not afford to play Fabregas alongside N’Golo Kante as a midfield duo if he wants to succeed this season – says Robson.
“Cesc Fabregas playing in a two in midfield is not athletic enough and Chelsea are going to be caught time and time again on the counter attack if Fabregas plays alongside Kante,” he told The Times’ The Game podcast.
“You can’t expect Kante to do all the running for him. You’ve got to have somebody in there that can defend much better and get around the field.
“That’s gonna be their weakness, all the time they’ve got Fabregas in the side they will be vulnerable.”
Podcast host Gabriele Marcotti then quipped: “Unless of course they play a midfield three.”
To which Robson agreed: “Of course, yeah.”
But the 52-year-old was not surprised Chelsea fell to defeat in their first match against the Clarets.
“I’m not overly surprised having seen them in pre-season,” he added.
“Having seen them in the Community Shield at Wembley and the FA Cup final as well.
“Last season they were really good defensively and I think they’ve become complacent.
“I’ve looked at David Luiz over pre-season and the last few games and he looks like a player who’s not alert, no alive, not defending with urgency.
“I would say the same about Gary Cahill.”
