Cobblers have confirmed that Shaun McWilliams underwent an appendix operation after the midfielder missed Saturday's Sky Bet League Two game at Oldham Athletic.
McWilliams has become an important member of Keith Curle's midfield this season and had started 17 of Town's last 18 matches in all competitions before missing out at Boundary Park, where the Cobblers drew 2-2 with Oldham.
The 21-year-old Northampton-born academy product has made 75 first team appearances in total, 19 of which have come this season.
The club initially said McWilliams was absent on Saturday due to illness but they have now confirmed he underwent an appendix operation in hospital on Saturday evening.
“It goes without saying that we wish Shaun well,” said manager Keith Curle.
“He had an operation on Saturday evening, the medical staff are looking after him and of course we wish him a speedy recovery.
"We look forward to having him back and available again as soon as possible.”
The club have not set a date for McWilliams' return to action but we all wish him a speedy recovery.