Ex-West Ham, Celtic, Man City midfielder Berkovic - Kayal must lift at Celtic
The 23-year old Israeli has had a huge dip in form at the beginning of the current Scottish Premier League season as he continues to negotiate a new deal with the Hoops whilst still harboring strong ambitions to make it to England's top flight.
But Berkovic, who played in the Premier League with Southampton, West Ham United, Blackburn Rovers, Manchester City and Portsmouth, feels that Kayal needs to concentrate on the job at hand and let his performances do the talking in regards to a future move to England.
"The best solution for Beram is to continue at Celtic and do his best work," he told the Daily Record.
"I've heard all of the things that have been said about his contract in recent months and I've heard about the possible interest from elsewhere. But to be honest these rumours are not helpful.
"If Beram wants to join a big club, and I mean a big club, he needs to be performing to his very best at Celtic. He has not been the same as he was last season but that's because he has not been concentrating on his job in hand.
"When you hear these rumours and then start talking about contracts, it means you are not fully focused and concentrating on your tasks.
"Beram needs to remove all of these thoughts from his head, reach an agreement and then have positive beliefs for Celtic.
"If he does that, his best form will come back and he'll get the big clubs watching him.
"If he doesn't have his full attention on Celtic and doesn't play to his best, no one will be keen to sign him."