Westwood has played 55 Northampton games over two spells
Northampton Town boss Aidy Boothroyd has released Ashley Westwood, Chris Arthur and Bas Savage.
Westwood, 35, was contracted until the end of December, while 21-year-old Arthur, who played eight games, would have been a free agent in January.
Striker Savage, 29,
arrived in August
and later signed a five-month deal, making 10 appearances in all.
"I made this decision now as I believe in being 100% honest with people," Boothroyd told
the club website
Centre-half Westwood, in his second spell with the Cobblers, made 14 starts in League Two.
"They can spend Christmas with their families, and they are free agents for the January transfer window," added Boothroyd.