Real Madrid star Cristiano Ronaldo is frustrated at missing out on his countries World Cup play-off against Bosnia.

The Portugal international has been ruled out of this weekend's first-leg clash due to an ankle injury picked up whilst playing for Real in the Champions League.

Ronaldo was examined by the Portugese medical team, who concurred with the diagnosis made by his Real Madrid doctors and promptly sent the winger back to Madrid where he will undergo further treatment on the troublesome ankle.

Speaking to AS the world's most expensive player said "It's a huge frustration that I cannot help Portugal, and more so in a moment no less decisive than this play-off against Bosnia.

"Nobody at this point, feels more sad than me, because to represent the Portuguese never stopped being one of the greatest moments of pride I feel as a professional footballer and as a citizen but now I have no alternative but to encourage my team from the outside."

Ronaldo then confirmed he would be in attendance at the match, cheering Portugal on.

"I'll be at the stadium to support my team-mates" he said.

"I am sure that keeping the spirit that we have witnessed, with unity, humility and solidarity, we will impose the quality of our football.

"In the end I will be with the team to celebrate the first of two steps that define our qualification for the World Cup. I have no doubt that we will be there."

The winners of the two legged play-off will go through to the World Cup finals in South Africa next year.