23-year-old Insua currently turns out for Boca Juniors in his native Argentina, although he is set to leave the club this January.
Since making his debut for Xeneizes in 2012, Insua has gone on to register upwards of 30 appearances, as well as spending a season on loan with Godoy Cruz where he was a first-team starter.
Brother of former Liverpool defender Emiliano Insua, the full-back has previously been linked with a move to West Ham, with the Premier League club tracking his availability over the summer - although negotiations failed to reach a late stage.
Reports in his homeland are indicating that Insua will be leaving Boca in January, with La Liga club Granada set to complete his signing in the coming weeks as they look to utilise the Pozzo family scouting network in the deeper regions of South America.
However, further reports are suggesting that Insua will transfer to Granada but will not be turning out for the Spanish club this term, with Mundo Deportivo reporting a potential deal straight to Pozzo sister club Watford.
The Championship side have acquired many players through the system, with loans from Udinese and Nazaríes leading the club to the Play-Off Final in 2013, before many signed on permanent deals that summer. In the summer window of this season, the Hornets signed Ecuadorian international full-back Juan Carlos Paredes in much the same manner, with Granada acquiring his rights from Barcelona SC, before selling him onto the Hertfordshire club for a negligible amount just days later.
It is still unclear whether Insua will be joining Watford on a permanent deal or as a loan when he completes his transfer to Granada, but, with cover at the left-back position needed for the Hornets, it would not be a surprise to see the 23-year-old tie his future down to the Vicarage Road club.