Llera needed 12 stitches in a head injury sustained on the first day of the season and the wound opened up during Saturday's win at Hartlepool, but the former MK Dons defender should be patched up to play.
Boss Phil Parkinson could therefore name an unchanged line-up as he looks to make it three wins out of three in League One.
Striker Andy Gray came off the bench at the weekend despite ongoing interest from Barnsley.
Midfielder Dean Sinclair is still sidelined with a knee injury.
The clash sees Parkinson lock horns with Orient manager Geraint Williams, who was his number two when the pair were at Colchester.