Empoli fear leading scorer Nicola Pozzi will miss the rest of the season with a knee injury while Fiorentina are waiting to discover if goalkeeper Sebastien Frey suffered a serious injury against Catania.
Pozzi damaged his cruciate ligament during his side's impressive 3-1 win away to Napoli on Sunday.
The Italy Under-21 international scored twice in the game, but picked up the injury in the act of netting his second goal.
He was stretchered off the pitch and Empoli coach Alberto Malesani admits Pozzi's injury is a 'bitter blow' as the club battle to stay in the top flight.
"Pozzi has sustained a serious injury," Malesani told reporters. "It is a bitter blow on this otherwise happy day.
"The first impressions of the medical staff are that the cruciate ligament has been broken, but we hope that is not the case.
"We are so happy for the win and the performance, but very sad about this terrible injury."
Meanwhile, Frey was forced out of Fiorentina's 2-1 win early in the second half and was replaced by Vlada Avramov.
The France international will undergo tests on the muscle problem, with Viola coach Cesare Prandelli hoping for a positive outcome.
"He will have to undergo checks in the next few days and then we will know something more," Prandelli told Sky Italia.
"I only hope not to lose him for a long time and that his injury won't be a bad one.
"Anyway, knowing Sebastien, he will do everything to come back as soon as possible."
Frey must be rated a severe doubt for Thursday's UEFA Cup second leg against Rosenborg, with Fiorentina 1-0 up from the first meeting.
Source: Sky Sports