MOGI DAS CRUZES, Brazil (AP) ― There is little not to like about Belgium defender Vincent Kompany at the World Cup. He has vision, poise and leadership ― all the qualities teams look for in a captain. Well, there is one downside ― he is injury prone.

So when all players bar one came cycling down to the training pitch on Thursday, there was a sudden worry Belgium’s World Cup campaign might not look so perfect after all, despite the opening 2-1 win over Algeria. Kompany stayed up at the team hotel to treat a groin strain. With Sunday’s game against Russia drawing near, alarm bells were quickly ringing.

Wilmots announced that the captain suffered from a “slight groin strain.” Kompany is not one to sit out a training for trifling issues. During the World Cup qualifier against Serbia he kept on playing with a broken nose and eye socket.

You cannot grin and tough it out when it comes to a groin injury, though, as it would only get worse.

Late Thursday, Wilmots added to the mystery by refusing to comment on the extent of the injury.

“We are waiting. We have our medical staff there,” was all he would tell the Belgian VRT network.

Even the players at training were surprised when Kompany failed to show up, as Wilmots had apparently kept them in the dark as well.

“Players don’t have to know everything,” he said.

Still, fellow defender Thomas Vermaelen expected Kompany “to be all ready by Sunday.”

If much has been made of injured stars like Luis Suarez for Uruguay, Radamel Falcao for Colombia and Cristiano Ronaldo for Portugal, it is because they stand out as forwards.

For Belgium, it is tough to think of a more important player than Kompany.

At 28, he is the symbol of Belgium’s revival as a football powerhouse, leading the country to its first World Cup in a dozen years. The defender has already led his club Manchester City to two Premier League titles in three years.