The 29-year-old swapped the Emirates for Old Trafford in January but has scored just one goal in 10 games for his new club and was dropped for last weekend’s FA Cup win over Brighton.
Rueda confirmed Sanchez had even contemplated not turning up for international duty ahead of Saturday’s friendly against Sweden before being persuaded to join up with his teammates.
‘It’s a difficult transition to go from Arsenal to Manchester United,’ he said.
‘He is sad because he wants to show his level. Fortunately he arrived with a great disposition. He knows that his teammates love him and respect him.
‘In February he asked me to stay at his club, to adapt, but his passion for the team made him come here. We hope we can help him.’
Sanchez is expected to start for Chile, who missed out on World Cup qualification, and the former Arsenal forward will hope to recapture a semblance of his best form having admitted he had been disappointed with his recent performances for his new club.
He said earlier this week: ‘As I am self-demanding, I expected something better,
‘After my arrival at United, it was hard to change everything very quickly. I even hesitated to come here [with the national team], I had asked permission to miss these games, but then I thought better and spoke with Claudio [Bravo] and told him that we should all be united to start things well.
‘The change of club was something that was very abrupt, it was the first time I’ve changed clubs in January. ‘Many things have happened in my life that are difficult.’
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