Manchester United manager Sir Alex Ferguson has admitted it is "a bad blow" to lose Antonio Valencia for four weeks with a hamstring strain.
The South American had only been on the field for 10 minutes following his introduction as a second-half substitute. However, after playing an integral role in Javier Hernandez's second in United's 2-0 Europa League win over Ajax in Amsterdam, Valencia was immediately replaced.
And Ferguson confirmed the news was grim, saying: "It is a bad blow for us. He has a hamstring injury unfortunately. It will be four weeks."
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