The 51-year-old trainer replaced the Serbian youngster after only 32 minutes of play when Fiorentina were 2-0 down, and Ljajic was not impressed with Rossi's decision.
|VIDEO: Rossi and Ljajic altercation
The pair were then split up by other staff members and substitutes before things got out of hand any further, but Fiorentina have nonetheless decided to let go of Rossi.
"I have decided to fire the coach for what we see as a serious incident. I am sorry for Delio Rossi because he's a good person. This is a serious matter, though. We will further talk about this tomorrow," club president Andrea Della Valle commented.
Fiorentina eventually managed to salvage a 2-2 draw in the remaining 60 minutes of the game courtesy of two goals from Riccardo Montolivo.