The player has been accused of punching and badly injuring a waiter in a bar in the early hours on Saturday. Mutu, whose nine-month drugs ban ends on Friday, has made no comment.
"I saw Adrian this morning briefly and it's better I don't tell you what I said to him because we are before the watershed. It's a serious thing, we will wait for the investigation," Fiorentina director Andrea Della Valle said in a club statement.
"We've got to wait because we don't know exactly what happened. We will act calmly. It's not the first time this sort of thing has happened but it's never been so serious."
Mutu has suffered an array of problems during his career.
He has been sorely missed by his team, who had a poor end to last season after losing in the Champions League last 16 and have surprisingly sunk to the bottom of Serie A this term.
Mutu was also sacked by Chelsea in 2004 for cocaine use and served a seven-month ban. He is still dealing with the consequences of the scandal after being ordered to pay over 17 million euros in damages to the English club.
The former Parma and Juventus player was banned again in January after testing positive for an appetite suppressant.
Mutu said it was unfair he should be suspended for taking a laxative pill which he did not know included banned substances.
Fiorentina have always previously stuck by the striker but Della Valle's statement suggested strong action could follow if he is found guilty of the assault.
