Coddington joins the Lions other young stopper, Joe Green, in the squad.
Coddington, 22, joined Huddersfield Town on a free transfer in July 2016 after his contract at Middlesbrough ended.
He never made a first-team appearance for Town but had a loan spell with Guiseley`s league rivals Wrexham and made fifteen appearances for Town’s under-23s.
He signed on a free transfer for the Cobblers from The Terriers in August.