The likes of John Egan, Conor Hourihane and Daryl Horgan could all make first starts in a green jersey.
O'Neill says these friendlies play an important role in his side's development.
Kick off at the Aviva is at 7.45.
The Republic of Ireland Under-19s need a win this evening if they're to progress to the European Championship finals.
Saturday's defeat to Sweden means Tom Mohan's side need to beat Group 7 hosts Belgium tonight, and hope the Swedes drop points to Italy.
Both games kick off at 6pm.