Messi has been on the sidelines since injuring his thigh in March

The 18-year-old Barcelona star has not played competitively since knocking Chelsea out of the Champions League at the beginning of March.

Argentina coach Jose Nester Pekerman said Messi was getting "better every day" in overcoming his thigh injury.

"But we don't want to make mistakes with his recovery," said Pekerman.

Messi played for just 15 minutes in Argentina's farewell game in Buenos Aires where Pekerman's team beat the national under-20s 4-0.

Pekerman is determined not to rush Messi back saying: "We'll go slowly, even though he is impatient."

Over the weekend, Messi had been more doubtful of his chances of playing the opener.

"I don't think I'll be in the team. I haven't played much, I've been out of action for some time," he said.

"I know I still have some way to go, but I'm relaxed, I know I have to keep working and feel better each day.

"I think I'll get into rhythm in the time left before the World Cup. I want to play the final and I hope we meet Brazil."

There was more positive news for the Argentinian squad over defender Gabriel Heinze, who missed eight months of the English Premiership season because of a ligament injury.