Belgium coach Roberto Martinez believes the absence of “irreplaceable” Romelu Lukaku from the Qatar World Cup will force his side to change the way they play, team officials confirmed on Tuesday.

The officials however confirmed that the striker has not been ruled out of the tournament yet.

Lukaku is struggling with a hamstring injury, having only recently returned from two months on the sidelines.

He is a doubt for the finals in Qatar, with Belgium opening their tournament against Canada on Nov. 23.

But team doctor Kristof Sas has described the latest injury as a “setback” rather than a fatal blow to the player’s FIFA World Cup chances.

“It is not yet a line through the issue, but it is a setback for the player himself, his club and the Red Devils (Belgium national team),” Sas said.

Martinez spoke last week about the importance of Lukaku in his side and how he covers a number of the attacking positions in the team.

Without him they would potentially need to restructure their midfield and forward line.

“At the Red Devils, he is irreplaceable,” Martinez had said. “Every national team has irreplaceable players. Look at Argentina with Messi, Croatia with Modric, Brozovic and Kovacic, Spain and Germany also have such players. That’s just how it works.

“With us it’s Courtois, De Bruyne and Lukaku. You cannot replace them one on one. If they don’t play, we have to play in a different way. If Lukaku is not there, maybe we should play with more attackers.”

Lukaku’s Italian club Inter Milan confirmed on Monday that the player had suffered a “myotendinous strain in his left hamstring” and would be monitored this week to ascertain he severity of the problem.

The 29-year-old returned to action last week and scored in a 4-0 UEFA Champions League win over Viktoria Plzen.

He also featured off the bench in the 3-0 Italian Serie A win over Sampdoria on Saturday.