"The truth is that he has traveled a lot," said Rijkaard. "He told us that he has hardly slept and was very tired. So I decided to leave him out of the squad.
"It wasn't just my decision, it was taken between the player, the medical staff and coach.
"It was the most intelligent decision to make, because if you're not physically 100 per cent, you can risk injury."
Rijkaard refused to speculate on whether he would've started Ronaldinho if he had been cleared to play and on this week's Champions League tie against Lyon, he added: "I hope to play him, but we'll have to see what happens in the coming days."
Asked why Robinho, who played with Ronaldinho for Brazil last week, started the game for Real Madrid in yesterday's 1-1 draw at Murcia, Rijkaard said: "I don't know if travel affects Robinho differently to Ronaldinho, I don't know what Robinho's situation is."