According to the Sun, the ball is now in the court of Saints manager Mark Hughes as Watford wait to see if he is prepared to sell a player who graduated from the club's academy and has spent his entire career at the south coast club.
Having made his debut for the club in 2011, Ward-Prowse has seen his stature at St Mary's grow over the years to become an influential player for the club since their return to the top flight in 2012.
The central midfielder has made 205 appearances for the Saints in all competitions and received his first England cap in 2017, alongside club teammate Nathan Redmond.
Although Ward-Prowse started more than half of Southampton's games last season, it remains possible that the 23-year-old will not be considered indispensable to the club, with Oriol Romeu and Mario Lemina among other available options in the middle.
Southampton have dipped into the market this summer to sign Stuart Armstrong, Mohamed Elyounoussi, Angus Gunn and Jannik Vestergaard for a combined total of £51m and Highes says his spending is complete for the summer.
Why would any Saints ‘fan’ be happy to see the back of James Ward-Prowse, especially for a miserly £10m? He’s still young, captained England u21’s & has never let anyone down playing for Saints. Watford would be a downward step & I’d be devastated to see him go. #SaintsFC— David Brewer (@banisteridol) August 7, 2018
The Saints avoided relegation from the Premier League by the skin of their teeth last season, having languished in the relegation zone for much of the season until previous manager Mauricio Pellegrino was sacked and replaced by the experienced Hughes late on in the campaign.