The defender left the clubs after seven years when he handed in a transfer at the beginning of the year when the transfer window opened.
There were suggestions last year that Jose Mourinho and Manchester United were interested in signing the player once the window opened but a bid never transpired and the 33-year-old was left to choose between the Hammers and West Bromwich Albion.
Puel told the Express: “We cannot have regrets because when Jose left the club it was a good moment for him.
“This position was difficult since the beginning of the season and it was important to find a solution for Jose and the club. Keeping an unhappy player is difficult.”
Fonte joined Saints from Crystal Palace in 2009 when the Saints were still in League One and managed by Alan Pardew.
West Ham head to the south coast after another disappointing week when they were beaten 4-0 at home by Manchester City. It was the third time that the two clubs have met this season, with City having won all three with an aggregate score of 12-1.