The former club doctor at Chivas Guadalajara, where Hernandez started his career before moving to Old Trafford for £7million last summer, revealed that he ordered the player to undergo a series of tests when he experienced acute migraines six years ago.
It has raised concerns that the concussion Hernandez suffered in an innocuous incident on Tuesday night, when he was hit on the head by a ball in training, might be linked to his previous problems in Mexico.
No KO blow: Ferguson has played down fears over hospitalised Javier Hernandez
'I don't know if there is a connection between the two situations. I'm not up to date with the current situation, we would have to speak to a neurologist.
'I don't know if this can affect him in the future. I'm sure United will send him to a specialist and the situation will be resolved.'
Hernandez fell ill after dinner and was so groggy that he was unable to communicate with United's medical staff in English. He was taken to a hospital in New Jersey and detained overnight, but released on Thursday.
While the rest of the squad flew to Washington DC, Hernandez followed later by car but Ferguson played down the concerns when Ortega's comments were put to him.
Fears: Hernandez could miss the start of the season after he suffered a concussion in training
'He went to hospital and was kept in overnight, but the scans were clear and they released him yesterday.'
Five players in Major League Soccer have recently been forced to retire on the advice of their doctors after suffering concussion, but Ferguson dismissed any suggestions that it could do any long-term damage to Hernandez's career.
'I don't see any history of players quitting because of concussion,' he added.
'It's something you don't want to happen, but usually time heals that.
'We won't be rushing Chicharito back. We'll only do it when the doctor says he can.'
All the president's men: Manchester United visited the White House in Washington DC
Goals from Anderson, Ji-Sung Park, Dimitar Berbatov and Danny Welbeck saw United maintain their 100 per cent record on tour, having won all four games, scoring 18 goals and conceding just two.
However, they face their toughest test against Barcelona at FedEx Field on Saturday, in a rematch of the Champions League Final in May.
US president Barack Obama was unable to meet the United party as the deadlock over America's $14.3trillion national debt reached crisis point, but Ferguson said: 'It was fantastic. Fascinating. I've been before but it's such an historic and incredible place. We all enjoyed it.'
The Barcelona squad also visited the White House but were prevented from jogging on the famous lawn by security staff.