With a freeze on buying players, Mancini is facing a uphill task to replace the likes of Rui Costa and Francesco Toldo who have made big money moves to Milan and Internazionale respectively.
The arrival of 23-year-old Baronio will come as a major boost with the versatile Lazio star likely to slot into the midfield.
The Roman club are also believed to be paying a good percentage of the young star's wages as they bid to help out the Viola through their turbulent times.
Another Lazio youngster, Emanuele Berrettoni, also looks set to join up - with the coach said to have been a big fan of the reserve player when he played for the Biancoceleste.
One player almost certain to be on his way, however, is last season's top-scorer Enrico Chiesa.
The brilliant marksman was a shining light in a tricky season, with first Fatih Terim and then Mancini watching the marksman show his prolific best throughout the campaign.
However, Chiesa is set to follow Toldo and Rui Costa out of the Artemio Franchi - because he does not like Mancini's tactical plans.
"I can not organise my team around one player," snapped Mancini when asked about the Chiesa situation. "I must consider all of the players I have at my disposal."
Another player who is not confident of success is veteran Angelo Di Livio.
"We are set for a very testing season," said the former Italian international. "It will not be easy to compete in Serie A."
Di Livio's view-point has galvanised opinions in the Italian media - who are beginning to speculate that the Italian top-flight may be without one of its most esteemed names after the coming campaign.
Fiorentina are 8/1 to be relegated from Serie A at the end of the season - click here for a full list of odds.
