Sussex opening batter Ali Orr faces another four weeks on the sidelines with a dislocated finger.
Orr, 22, was hoping to return to the squad following a knee problem.
However, he suffered the new injury while playing club cricket for Eastbourne on Saturday.
He was building up his fitness before a planned return for Sussex in their One-Day Cup match against Gloucestershire this Friday, only for his comeback to be delayed.
Orr was one of the bright spots for Sussex in the County Championship last season, as the left-hander passed 1,000 first-class runs in what was his first full campaign in the side.
