Injured midfielder Chris Clements will miss a maximum eight weeks of Mansfield Town’s season.
Stags had feared the influential playmaker may have had to sit out as much as four months of the campaign after he damaged medial ligaments against York City.
But scans this week revealed the injury is not as bad as first feared.
Said Cox: “The news is good for us, we have got an excellent physio in Simon Murphy and Chris will be working hard with him to get fit again.
“He will be a big loss for us and we want him back playing again as soon as possible.
“I am gutted for the player, He has always been honest with me and has been playing well and consistently.
“I always knew we had a player in him and he has come on leaps and bounds since joining the club.
“He is a better play now than when he joined us, and that is great credit to our coaching staff.”
Fellow midfielder Jamie McGuire believes Clements will come back stronger following his injury setback.
“Chris has been playing really well and I feel for him,” he said. “He is a strong character and he will come through it.
“He is a very good player, he finds a pass, he sees a pass, but he always digs in when we need to dig in during a game.”
Mansfield go in to the game on the back of an impressive six game unbeaten run which has seen them climb to eight in the early table.
Aidy Boothroyd’s Northampton have struggled to recapture last season’s form and currently sit 22nd in the table without an away win all season or any wins in their last five games.
Mansfield centre-back Martin Riley misses the game following a three match suspension, while winger Lindon Meikle is also suffering from a knock to his hip flexor.