"There may be one signing," he told a news conference promoting their North American summer tour. "We'd maybe like to get one good player to the club, but it's not easy in the present day climate. We're still assessing."
United's quest for an unprecedented fourth straight title was blocked by Chelsea, who finished one point ahead.
"It was always difficult to go for four trophies in a row, but we felt we could have done it," said Ferguson. "The challenge is to bring that trophy back. That's an important trophy because the competition is so fierce in England."
Ferguson added that he liked the make-up of his squad.
"Sometimes you have to have trust and faith in what we've developed in the last few years and I'm going to stick with that, or most of it," he said.
"The structure of our squad is good - the ages, the balance of the squad, the numbers. They are all good young players."
He also pointed out that United had already signed 21-year-old World Cup-bound Mexico striker Javier Hernandez from Guadalajara and defender Chris Smalling, 20, from Fulham.
Regarding their North American tour, Ferguson said setting up a training camp this summer in Chicago followed by three games against Major League Soccer teams and a final match versus the MLS All Stars would be good preparation for next season.
"We've got to get our show on the road," he said. "That means concentration and a rhythm of the game has got to be found quickly after the disappointment of last season.
"We want to start the season very quickly, start on the front foot."
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