Hernandez, who joined his new team mates in Houston on Monday, could make his Red Devils debut in Wednesday's game against the MLS All Stars.
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Ferguson, who will wait for news on the 22-year-old's fitness before deciding whether to play him, paid tribute to the club's scouts who plucked the forward from Mexican club Chivas de Guadalajara.
"I think our scouting people deserve 10 out of 10 for identifying him before the World Cup and I think if we had been trying to negotiate after the World Cup it would have been very difficult," said the Manchester United boss.
"I think a lot of teams would have been after him and it would probably have cost us two or three times more," he added.
Manchester United did not disclose the transfer fee they paid to Chivas but media reports have placed the deal as worth around £7 million, including United playing a friendly in Mexico on Friday.
Ferguson was full of praise for the Mexican club for helping keep the deal quiet.
"Our relationship we have built with Chivas has been excellent, they really were very accommodating in everything - the amazing thing was that no-one in the club said a word.
"At Manchester United we find that almost impossible, news always leaks out at our club, but Chivas kept it quiet which was marvellous asset for us and full marks for their professionalism.
Hernandez will play half that game for Chivas and half for his new club but his debut may come earlier in front of thousands of Mexican fans in Houston.
"He joined us today and so we have to ascertain what he has been doing in the last few weeks physically, we would like to use him in part of the game on Wednesday - partly because I know there is a big Mexican population in Houston and it would be a very exciting attraction for them," said Ferguson.
"Secondly we want to try to integrate him into the team as quickly as possible so those are the reasons we would like to play him but we want to just have a chat with him and see what he has been doing physically.
"I don't think it would be wise to play him without having any real preparation for this game."
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