The wing-back has struggled since his summer arrival from Eintracht Frankfurt.
But Kovacevic said: “Let's give him time.
"He arrived less than two months ago, he has to adapt to a new football and a new country. He may not be Messi, but has everything to do well. I would have paid to have someone like him when I was playing.
"With all his crosses, I would have scored even more goals."