Prandelli took over in early November from 56-year-old Iachini who had been in the post less than a year. "(Iachini) will direct training and will resume contact with the team this morning," the Tuscany outfit said.
La Viola dropped two places under Prandelli and are 14th, seven points above the relegation zone, with their next game at Genoa on April 3. Prandelli stood down on Tuesday with the former Italy coach explaining in a letter he was unable to follow the current rhythm of football.
"I came here to give 100 percent, but as soon as I had the feeling that this was no longer possible, for the good of all I decided to take my step back," the 63-year-old said.