The Brazilian has spoken of needing rest to heal a hip injury in time for the World Cup.
Mourinho said: "Oscar was our best player for months, from August to November or December. He was fantastic. And after that, he was up and down. The reasons why I don’t think I should say because some of them are from the personal side of the man, not the player.
"But after that he was up and down. He arrived in the crucial moment of the season in a down: injuries, he couldn’t train, he was trying to arrive to the game but didn’t, he was a doubt for the game. And the game was too big to play with a doubtful player, so he arrived in the crucial moment of the season in a low. I can imagine, in a couple of weeks, he will be in a high and during the World Cup he will be in a high."
Asked whether the player’s present concern should be his club rather than next month’s World Cup, Mourinho said: "There are things you can’t resolve."
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