Leinster have confirmed that Jamison Gibson-Park is not included in the training squad before their opening United Rugby Championship match against the Johannesburg Lions at Ellis Park.
The Ireland international joins a growing list of players unavailable for selection due to injury, with Cormac Foley, Jordan Larmour, Diarmuid Mangan and James Culhane also sidelined.
Gibson-Park's absence stems from a minor groin injury sustained while starting two of Ireland's summer internationals against Australia and New Zealand.
In contrast, Andrew Porter, Tommy O'Brien and Joey Carbery may feature on Saturday after all three returned to full training.
Porter missed the summer Tests through a calf injury, while O'Brien was previously sidelined by a groin issue.
Carbery, who re-joined the province from Bordeaux-Begles over the summer, has intensified his training programme as he seeks to clear an anterior cruciate ligament injury.
Leo Cullen's side stated there are currently no updates regarding Jack Boyle, RG Snyman, Caelan Doris and Paddy McCarthy.
The club did not provide further details on the status of these four players.