The experienced trio of Craig Cathcart, Tom Cleverley and Dan Gosling are in talks about new deals with Watford.
The Hornets have said "there should be no rush" in determining the futures of Cathcart, 34 and Cleverley, 33, who are out of contract this summer.
And while Gosling, 33, had his contract terminated by mutual consent in March after sustaining an Achilles injury, a new deal remains possible.
Meanwhile, Britt Assombalonga and Leandro Bacuna have been released.
Assombalonga, 30, returned to the club in January and made 11 appearances, but the additional 12-month option on his contract has not been triggered.
Former Aston Villa midfielder and Curacao international Bacuna made 14 Championship appearances for Watford after moving to Vicarage Road in December.
The futures of Cathcart, the longest serving player at the club with more than 250 appearances, and Cleverley, who has been with the Hornets since 2017, remain up for debate following the arrival of boss Valerien Ismael.
"We must continue to assess what is best to support our head coach Valerien so it is important that we do not close off any options right now, while it is still early in the summer," said technical director Ben Manga.
While Gosling's own future is discussed he has remained with the club to continue his rehabilitation.