The 29-year-old Dutchman sustained the injury in the recent friendly with Barrow and will be sidelined for at least a fortnight.
Rovers physio John Dickens said: "Jos damaged his stomach during the match against Barrow the other day.
"He will now have to go in and undergo a repair. He's basically going to be having a hernia repair on Saturday morning and won't be back in training for a couple of weeks."
But Martin Woods has returned to full training following his hernia operation. The 23-year-old Scot has resumed full training and is set to feature against former club Rotherham on Saturday.