Australian international scrum-half Chris Whitaker has been ruled out with a broken leg for up to 10 weeks and he could be joined on the sidelines by Girvan Dempsey (leg).
At this stage it is unclear the exact length of time the Ireland full-back will be out for and an update will be made on his availability over the coming days.
Both Dempsey and Gordon D'Arcy will be assessed by the medical staff this week and it is hoped that both of their outlooks will then be clearer.
Meanwhile, in other team news Ireland Under-20 Grand Slam winning scrum-half Paul O'Donohoe has been called up to the extended Senior squad for Friday's game. O'Donohoe is joined by fellow Grand Slam winner - and Belvedere College schoolmate - Cian Healy, while Chris Keane could also be considered after injury.
The enlarged squad includes, in total, 10 Ireland internationals.
The team will be announced on Thursday lunchtime.
Leinster squad to face Ospreys
FORWARDS: Cian Healy, Ollie le Roux, Brian Blaney, Bernard Jackman, Juan Gomez, Stan Wright, Leo Cullen, Cameron Jowitt, Malcolm O'Kelly, Devin Toner, Keith Gleeson, Shane Jennings, Kevin McLaughlin
BACKS: Chris Keane, Paul O'Donohoe, Cillian Willis, Felipe Contepomi, Jonathan Sexton, Christian Warner, Rob Kearney, Michael Berne, Gordon D'Arcy, Brian O'Driscoll, Gary Brown, Shane Horgan, Luke Fitzgerald
REFEREE: Andy Macpherson (SRU), SUB REFEREE: Tim Hayes (WRU), TOUCH JUDGE: Matthew Alpin (WRU), TMO: Tony Rowlands (WRU)
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