Defender Michael Hefele is unlikely to play again this season because of an Achilles problem, according to Nottingham Forest boss Martin O'Neill.
The 28-year-old German has played 18 games this season, but has not featured since being injured in the 4-2 win over Leeds United on New Year's Day.
O'Neill told BBC Nottingham Sport Hefele needs surgery: "I am not likely to see him this season.
"It may be early to make that prognosis but I don't expect to see him."
Forest will also be without Hefele's fellow defender Michael Dawson for up to six weeks.
The centre-half, 35, returned to training last week following a hamstring injury, but suffered another setback during O'Neill's first training session.