Gillingham boss Mark Stimson accepts it will be tough to find a replacement for departing defender Darren Dennehy.
The on-loan centre-back has attracted praise for his performances since joining the Gills from Cardiff in mid-January.
However, his last game came in Saturday's 2-0 loss to Norwich, meaning youngster Tom Wynter and the more seasoned Josh Gowling will vie for the vacant position.
"Someone needs to step in and do half as good a job as Darren," Stimson told the Kent Messenger.
"It's a tricky position, especially if you don't do it correctly and concentrate. That's one of the biggest problems you get at this level - concentration.
"We've got Josh or Tom and we'll have a look in the week to see who we think is up for that challenge. It's between youth and someone who has played a few games."