Fergie: Hernandez would have cost us three times more had we signed him after the World Cup

Sir Alex Ferguson believes Manchester United could have been forced to pay up to £21million for new striker Javier Hernandez had they waited until after the World Cup to sign him.

United paid £7m to sign Hernandez in April, before the Mexico striker impressed at the World Cup with two goals for Mexico, a performance which Fergie said could have driven his price up threefold had he still been on the market.

Hernandez is set to make his United debut on Wednesday night in a friendly against an MLS All-Stars team in Houston and Fergie said he was glad he was able to sign the 22-year-old striker before he came to the world's attention.

"I think our scouting people deserve 10 out of 10 for identifying him before the World Cup," said Fergie. "I think if we'd been trying to negotiate after the World Cup it would have been very difficult.

"I think a lot of teams would have been after him and it would probably have cost us two or three times more."

United signed Hernandez from Mexican club Chivas, whom they will play on Friday in Guadalajara on the final leg of their pre-season tour, before returning home to continue their build-up to the new campaign.

And Fergie said he was keen to see Hernandez in a United shirt as quickly as possible, to assess his fitness, with Wayne Rooney only returning for pre-season training today and Michael Owen set to mis the start of the season with a hamstring injury.

"Javier has joined up with us and so we have to ascertain what he's been doing in the last few weeks physically," said Fergie. "We'd like to use him in part of the game on Wednesday. We want to try to integrate him into the team as quickly as possible.

"But we want to just have a chat with him and see what he's been doing physically. I don't think it would be wise to play him without him having had any real preparation for this game."

Fergie confirmed Hernandez will play 45 minutes for his former club Chivas and the second-half for United when the two clubs meet in Mexico. "He'll play half for Chivas and half for us, which I think is a nice tribute to his former team," said Fergie.

"We were happy for that to happen. I think it's more important for the half he plays for Chivas than the half he plays for us in that particular game, simply because he's one of their star players."

Asked what would happen if Hernandez scored for Chivas against United, Fergie joked: "He'll be fined and transferred back!".