The Chile international has been strongly linked with a move to the Etihad Stadium to bolster City's midfield.
Reports in Italy claim Pizarro will join the Blues on loan until the end of the season.
"We are only negotiating with Manchester City for Pizarro," Baldini was reported as saying on www.asromanews.it. "We will try to complete the deal before tonight."
The 32-year-old Pizarro has made just seven league appearances for Roma this season. He joined the club from Inter Milan in 2006 and is under contract with the Giallorossi until June 2013.