The Australia international has slipped from the starting lineup under Alan Pardew.
The Australian has been a vital figure at Selhurst Park under a succession of managers, but his importance at Palace has been downgraded somewhat under Alan Pardew, and the 31-year-old has yet to make a Premier League start this season.
Jedinak isn't entirely stricken from the first team picture, and has appeared in three out of five games so far this season, but it is clear that the former Newcastle boss doesn't see the Australia international as a vital member of the side, with Yohan Cabaye and James McArthur instead preferred in the middle of the park.
Nevertheless, there is little doubt that Jedinak is anything but a strong Premier League player, and any move could depend on how determined he is to be a main man somewhere, or continue to fight for a first team chance at a club he has spent four years.
Watford have signed plenty of individuals this summer, but none will have as much experience in the Premier League as Jedinak, which could prove to be vital in their attempts to stay up this season.
Coupling the Australian alongside Etienne Capoue would also ensure a powerful midfield combination for the Hornets.
And at the Baggies, Tony Pulis is known to be a fan of Jedinak, having worked extremely well with him during his short but impressive stint at Selhurst Park in the 2013-14 season.
West Brom are expected to be busy on deadline day pursuing a number of deals, though much of their business could be dependent on high profile outgoings.
Regardless of that, it wouldn't be a surprise to see Pulis interested in Jedinak should he become available, especially for the modest fee of £3 million.