The Sunday Mirror says the City boss wants the resources to bring in a forward and defender as well as the versatile De Rossi.
The Italian has been monitoring Fiorentina’s attacker Stevan Jovetic, although the 22-year-old Montenegrin is rated in the £25million bracket.
The growing tensions between Mancini and his employers have been the talk of City’s Carrington training ground.
A City insider said: “Mancini is unhappy that the club are saying they can’t, or won’t, back him in the market this month.
“He understands that FFP is already having an impact, but he feels that after investing so many resources to get to the top of the league, the challenge could be undermined by the reluctance to bring in one or two more players.”