Watford defender Neuton is set to miss the majority of this season's promotion run-in after the Brazilian dislocated his shoulder in training this week.
The 22-year-old had previously been sidelined with a toe problem and has only made seven starts this season for the Hornets.
"We think he has a dislocated shoulder," Watford head coach Gianfranco Zola said.
"He was back in training and he had a problem there so unfortunately it’s another injury for him, he’s a very unlucky boy.
"We don’t know if he'll be out for the season yet - he has to keep it in a bandage for a week to keep it still and locked.
"I think in a week or so he’ll have another scan and see a specialist."