The Viola boss has been dismissed after punching the Serbian midfielder after an early substitution in Wednesday's Serie A game against Novara
The 51-year-old 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.
He player sarcastically applauded his coach while making his way to the bench, thus infuriating the Fiorentina boss. Rossi pushed the 20-year-old against the back of the dug-out before aiming a punch at Ljajic.
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.