The 51-year-old ensured League Two football at Bootham Crescent last season but York have managed just two wins in the current campaign.
His final game in charge was Saturday's 3-1 home defeat by AFC Wimbledon which Wilcox told BBC Radio York afterwards was: "Shambolic in a nutshell.
"Nowhere near good enough. Not acceptable. We're fighting for our lives at the bottom of the league."
Northampton are scheduled to visit the fine city of York on Boxing Day although the future at Sixfields remains up in the air after Tuesday's latest developments off the field.