The 21 year old has three caps under his belt already and was widely expected to be called up for up and coming internationals.
But the player says that he would stay behind even if he was picked.
He told Sky Sports: "I was talking with the secretary of the Croatian FA Zorislav Srebrnic and I told him that I'm not physically ready to play for Croatia.
"For that reason it is better for me to stay in Blackburn. That is what Sam Allardyce also told me, and so I will able to work on some special training when players are on international duty.
"I agree with the manager. I know how I can play when I'm completely ready and I know I'm really not in top form.
"So it will be the best for all of us if I don't travel back home and stay in Blackburn.
"Even if Slaven Bilic would call me to the senior team my reaction would be the same."