Watford players were left stunned after being compelled to stay for two nights at the Sopwell House hotel, located just four miles from their training base at London Colney.
The Championship side have dropped five of their last six fixtures, prompting owner Gino Pozzo to order a sudden boot camp as a team-building measure.
Several key members of the squad are described as livid and confused about having to be away from home both last night and Tuesday.
Sopwell House, a upscale hotel, sits close to the training ground that sits directly beside Arsenal's facility.
Watford boss Alessio Dionisi, who took charge in June, faces intense pressure as the team prepares to meet fellow relegation rivals Norwich on Saturday, followed by a home clash with newly promoted Lincoln.
Should the Watford side lose both matches, Dionisi could become the latest manager to be dismissed, a pattern familiar to the Pozzo family who also own Udinese.
The Pozzo owners have previously mandated similar training camps near the club's base, claiming they have produced results despite player discontent.
During the summer, Watford added twelve new signings but did not travel abroad for a pre-season, missing the usual bonding period for newcomers.
With the club currently fourth from bottom and only three wins to their name, the decision to intervene is unusual among peers.
