Jack Rodwell has since arrived at the club, and Mancini has acknowledged that it is hard to conduct good business in the transfer market.
"What I said last time was not because I had a problem with Brian - I don't," Mancini said.
"But when you are a manager, you want maybe sometimes to buy a player quickly. At the same time I know it is difficult because the market is difficult. It was important to start with one (signing) and now it is important to think about the game on Sunday.
"Then we have about 10 days until the end of the market and I think we will do [more business] - I am sure."
City will host newly-promoted Southampton in their season opener on Sunday.