Barnsley top scorer Craig Davies has been sidelined for up to six weeks with a hamstring injury.
The Wales striker, who recently returned to international action against Scotland after a five-year absence, limped out of the Tykes' weekend victory at Charlton.
It is a further blow for boss Keith Hill, who is already without first-choice central defenders Jim McNulty (hamstring) and Martin Cranie (ribs) for Tuesday's home clash against Crystal Palace.
Hill is expected to recall Marlon Harewood to his starting XI after the ex-West Ham player replaced Davies, who has netted eight goals this season, at the Valley.
Harewood should partner Chris Dagnall in attack, but Hill also faces an anxious wait over the fitness of midfielder Stephen Dawson who is struggling with illness and a knock picked up against Charlton.
However, Barnsley have received a fitness boost with Egypt international Mido scoring on his return for their development side on Monday.
The ex-Spurs and Middlesbrough striker joined the South Yorkshire club in a shock summer move, but has yet to make a first-team appearance after rupturing his hamstring before a pre-season friendly.