SAINTS have announced their retained and released list, with the club intending to keep all their out-of-contract first-team players.
That follows on from the news earlier this week that centre-half Radhi Jaidi has signed a one-year extension to his St Mary's stay.
Harding, Butterfield and Martin all earned another year after clauses in their contracts were automatically triggered.
Assuming all six players do remain at the club, it gives Saints a healthy-sized squad going into the summer, ahead of their return to the Championship.
And it is also perhaps an early indication that manager Nigel Adkins doesn't plan to be too active in the transfer market over the coming months.
Saints have released five players, but none of those have seen any first-team action this season.
Unsurprisingly, midfielder Anthony Pulis' unsuccessful stay at the club has finally come to an end.
The 26-year-old joined Saints in August 2008, but never played a minute of first-team football for them.
Pulis heads for the exit door along with youngsters Sam Argent, Tony Garrod, Callum McNish and Ryan Tafazolli.
All those players will officially depart the club at the end of June, when their contracts expire.
In a statement on the club's official website, Saints thanked the departing players for their efforts and wished them well in the future.