Brazil striker Robinho is doubtful for Wednesday's World Cup second round match with Ghana, team doctor Jose Luis Runco said on Monday.

Robinho ended training early on Sunday after suffering a twinge in his right thigh.

The player, whose speed and trickery gave Brazil a new dimension in a 4-1 win over Japan in their final group game on Friday, was seen to clutch his thigh during shooting practice.

Robinho missed practice on Monday. Instead he stayed in the team hotel undergoing physiotherapy.

Runco said Robinho had shown an improvement but would undergo an MRI scan on Tuesday to determine the extent of the injury.

"We'll wait for the results of this before making any decision," said Runco.

"If it's not a sprain, then he's free to train and play as soon as he doesn't feel any more pain."

Runco added it was very unlikely that Robinho's injury would be serious enough to force him out the tournament.

Robinho began Brazil's first two games against Croatia and Australia on the bench, coming on in the second half.

He then replaced Adriano in the starting lineup for the Japan match and Brazil looked much livelier throughout.

Coach Carlos Alberto Parreira has not yet decided whether Robinho will start against Ghana, if he is fit.