Ferguson is keen to add one more new face to his squad before the quest to regain the Premier League title from Manchester City begins next month.
"There will possibly be one more," he said. "We have always done well in terms of getting players in at the end of the season. That is the right time.
"But always in a European Championship or World Cup year, there is a delay in the transfer industry.
"That is over now and we are still trying to get one more in."