Cobblers midfielder Ryan Watson is facing an extended period on the sidelines after breaking his collarbone during Tuesday's defeat to Peterborough United.
Watson was enjoying another fine game for Town when he landed awkwardly following a strong challenge in midfield after 64 minutes.
He was in visible agony as he left the field, and while it was first thought the 26-year-old had suffered a dislocated shoulder, manager Keith Curle later confirmed it is a potentially more serious injury and one which will require surgery.
"It's a broken collarbone and he's going to have surgery so that's going to be a period of time out just when I thought the lad was finding his feet," said Curle.
"He was just understanding what we're demanding from him and he was enjoying his football so it'll be a lot of hard work for the lad now to get himself back fit.
"He needs to face the surgery and treat it as a challenge."
Matty Warburton was also taken off with an injury during Tuesday's game.
Curle added: "Matty Warburton has a nasty gash on his ankle. We'll take a look at it tomorrow and find out the extent of it then."