Watford must make a decision quickly over trialist Kiko Macheda.
The former Manchester United and Cardiff City striker is training with Walter Mazzarri's Watford squad.
But he could emerge as a target for Napoli after Arek Milik suffered a knee injury on Poland duty.
Macheda is also currently a free agent and looking for a new club after his deal with Cardiff expired.
Also on Napoli's radar is former Crystal Palace striker Marouane Chamakh.