Rhys Bennett has been ruled out of Rochdale's game against Gillingham.
The defender was substituted after just eight minutes of Saturday's 2-1 defeat at Bristol Rovers with a knee injury.
Bennett, 21, has undergone a scan to ascertain the extent of the damage but manager Keith Hill has revealed he is not optimistic the player will feature for the club again this season.
The former Bolton trainee joins forward Terry Gornell (groin) and midfielder Reece Gray (broken leg) on the injury list.
Midfielder Ritchie Jones may feature in Hill's squad against the Gills after he returned to training following an ankle injury.
The game will be the first of three consecutive home matches for Dale as they look to move clear of danger in the bottom half of the npower League Two table.
Gillingham will hope to extend Michael Richardson's loan stay ahead of their trip.
The Newcastle midfielder, 21, saw his one-month deal expire following Saturday's 1-1 draw at Morecambe, after which manager Martin Allen expressed his desire to keep hold of the player for a longer spell.
And the Gills boss will be keen to tie up an extension to his loan stay ahead of the clash at Spotland.
Richardson made his first start for Gillingham at the Globe Arena but was replaced at half-time by the fit-again Charlie Allen, who made his return from a wrist injury and put in an impressive second-half display.
Myles Weston will again be assessed having missed the last four matches with an ankle injury, while Steven Gregory and Danny East, both rested at the weekend, will look for involvement.