The Mexico frontman spent Tuesday night in hospital after complaining of headaches during a meal after training. Medical staff eventually gave Hernandez the all-clear but Ferguson has already ruled the 22-year-old out for a fortnight and he was driven down to Washington from New York on Thursday rather than making the 220-mile journey by plane. Ferguson downplayed the impact of neurological problems in Hernandez's youth, which were revealed in Mexico on Thursday. But, ahead of his side's encounter with Barcelona on Saturday, the United boss insists he will adopt a cautious approach with Hernandez. "I am not aware of that," said Ferguson, of the claims in Mexico from Rafael Ortega, the doctor at Hernandez's former club Chivas, before recounting the events of Tuesday evening. "He was hit on the top of the head with the ball. When he was back at the hotel taking his meal he was sick. "He had headaches, so we removed him to the hospital where he stayed in overnight. They did the MRI scans, released him yesterday and he travelled down today. "Concussion is something you don't want to happen but usually time heals it and we'll give Javier plenty of that. "We won't be rushing him back. I'll only bring him back when the doctor tells me I can." There is better news surrounding Antonio Valencia, who suffered an ankle injury during the opening match of Ecuador's woeful Copa America campaign which was first feared to be a repeat of the injury that forced him out for six months last term. Those worries were quickly allayed but Ferguson still sent him back to Carrington for extensive rehabilitation work, which seems to have paid off. "Antonio's training now," said Ferguson. "He has been cleared and training for a week now. We expect him to be back for the start of the season." Meanwhile, United square up to their Champions League conquerors in front of 80,000 at FedEx Field with full-back Patrice Evra keen to find a more competitive environment to make up for that shattering Wembley loss. "I give Barcelona a lot of respect but I'd like to play against them again in the Champions League final and win," said Evra. "I have already lost to them twice and it's very painful. "At the moment they are the best team in the world, which is difficult for us to accept because that is what we want to be."
