Torquay United defender Aaron Downes is set to undergo knee surgery on Monday after suffering an injury in training.
Gulls boss Alan Knill said the club would not know how long the 28-year-old centre-back would be out of action until after the operation.
"It could be four weeks, or it could be four months - we just won't know until Monday," he told BBC Radio Devon.
Torquay have cover after signing 20-year-old defender Anthony O'Connor on a one-month loan deal on Tuesday.
"We had to move quite quickly," said Knill.
"We've seen him play at Blackburn and at Burton. We've got some connections in the north west and we made a couple of phone calls - and credit to him, he said 'yes' straight away."