Napoli defender Miguel Britos is set to join Watford.
Calcionews24 reports Udinese and Napoli are close to agreeing Allan's move for a fee approaching €11m, with the two Napoli players moving to Vicarage Road as part of the deal.
Britos, who has also attracted interest from Besiktas, is said to have agreed to join the fellow Pozzo-owned club and Inler is also widely reported to be part of the transfer package.
Gokhan Inler could follow Britos to Watford.