The NPL leaders lost both players to injury in the 1-0 win over the Newcastle Jets Youth on Sunday. Bailey went down with his knee injury early in the second half and Ireland hurt his ankle midway through the first.
Olympic coach Michael Bolch said Bailey received results of an MRI scan on Tuesday which confirmed their worst fears and the need for surgery.
There are hopes though that Ireland could return. Bolch said Ireland has been told he could miss up to four weeks, giving Hamilton an outside chance of having him on board for the semi-finals, which start August 20-21.
Bolch said Simon Mooney or Andrew Swan could start in a reshuffled line-up with Rhys Cooper moving back to central midfield for Bailey. Tom Pullin, who came on against the Jets Youth, will fill-in between the sticks.
Bolch said he was hopeful of having Ireland back for the finals but the loss of Bailey was a blow.
“He’s our workhorse in the middle of the park and breaks up a lot of the opposition play,” Bolch said.
“He’s a massive loss but we have options with Simon Mooney and Andrew Swan, who have been on the bench. Rhys has been playing wider but we may have to bring him back into the middle with Leo [Bertos]. We might have to change the way we play a bit.”