Sussex leg-spinner Mushtaq Ahmed will have an exploratory operation on his right knee on Monday.
Mushtaq, who underwent surgery on the same knee at the end of April, suffered has suffered a fresh cartilage tear during the recent Championship defeat to Lancashire.
The 38-year-old will not know the full extent of the latest injury until the operation has been carried out.
If the cartilage tear is extensive then Mushtaq would miss the rest of the season, although if it is only minor he could be back at the start of August.
