Croatia and AC Milan striker Nikola Kalinic has been sent home from the World Cup, leaving Croatia with 22 players.

Croatia and AC Milan striker Nikola Kalinic has been sent home from the World Cup after reportedly refusing to come on as a substitute during the country's opening game win against Nigeria on Saturday.

Confirmation camed Monday, when coach Zlatko Dalic, who has preferred Mario Mandzukic and Andrej Kramaric up front, gave a press conference later today.

Widespread reports suggested that Kalinic complained of a back problem when Dalic asked him to go on in the 85th minute when Croatia's comfortable 2-0 win was already secure.

Winger Marko Pjaca went on instead, but Dalic apparently wasn't convinced by Kalinic's excuse.

Once of Blackburn Rovers, Kalinic, who scored just six goals in 41 appearances for Milan on loan this season but will now cost the Rossoneri €25m as part of an obligatory agreement to buy from Fiorentina, hasn't started any of Croatia's last four internationals.

He did start both legs of the UEFA qualifying playoff against Greece in November 2017, but his last start came in a friendly defeat at the hands of Peru in March of this year and woeful club form is seemingly responsible for the 30-year-old losing his international place.

It would appear that Kalinic is not happy being a backup and Dalic has taken action.

World Cup nations are only allowed to replace players in their squads until 24 hours before the start of the tournament, and only then in the event of injury. With Kalinic now believed to be gone, it means Croatia will have to continue their tournament with just 22 players.

Perhaps worryingly, there is no other No. 9 in the squad besides Mandzukic. But Dalic seems to understandably value unity above the potentially toxic influence of an unhappy player.