Sheffield Wednesday defender Aden Flint is facing a spell on the sidelines with a hamstring injury.
The 31-year-old joined the Owls on a season-long loan from Championship rivals Cardiff in October and has made four appearances.
He suffered the injury in the 3-0 defeat by Rotherham last week and scans have revealed he needs an operation.
"It's frustrating for everyone as it was so innocuous at the time," boss Garry Monk told the club website.