Leon Barnett has signed a new one-year contract to stay with the Cobblers, with an option to stay on for another 12 months.
The 32-year-old was offered a new deal by boss Dean Austin last month, and he has now put pen to paper.
The former Norwich City and Wigan Athletic defender joined the Cobblers from Bury last summer, but suffered a frustrating season.
He was a regular in the first team until September, when he suffered an Achilles injury, and although he returned to action again by the end of the year, he suffered a relapse, and then once fully fit again in February struggled to nail down a regular place in the first team, with Jordan Turnbull partnering Ash Taylor.
Barnett, who played in the Premier League for the Canaries and the Europa League for Wigan, returned to the Town starting line-up for the derby at Peterborough United on Easter Monday, and was a first choice for Dean Austin in the remaining games of the season.
In all, Barnett made just 16 starts and two substitute appearances last season, scoring once in the 2-2 draw at Southend United in September.
His signing means the Cobblers currently have four central defenders contracted for next season, with Barnett joining Taylor, Aaron Pierre and Turnbull.
Barnett’s decision to accept the new deal also means the Cobblers now have 26 players under contract for the Sky Bet League Two season, that starts in August.
Cobblers players under contract 2018/19 season
Goalkeepers: Richard O’Donnell, David Cornell, Luke Coddington, James Goff
Full-backs: Shay Facey, David Buchanan, Joe Bunney.
Central defenders: Ash Taylor, Leon Barnett, Aaron Pierre, Jordan Turnbull
Midfielders: John-Joe O’Toole, Matt Crooks, Shaun McWilliams, Daniel Powell, Sam Foley, Jack Bridge, Yaser Kasim, Morgan Roberts, Sean Whaler.
Forwards: Kevin van Veen, Andy Williams, Billy Waters, Sam Hoskins, Dean Bowditch, Joe Iaciofano