O'Neill has already lost West Brom duo Gareth McAuley and Chris Brunt, as well as Rotherham midfielder Michael O'Connor for the fixture in Adana.
Derby winger Jamie Ward (foot) has now further compounded his selection woes, with on-loan Birmingham midfielder Shane Ferguson also a doubt through illness.
Speaking to Sky Sports News as his players departed for Turkey, O'Neill revealed Hibernian duo James McPake and Ryan McGivern would bolster his ranks.
"We're calling in James McPake and Ryan McGivern," O'Neill said.
"We got late notice of Jamie Ward, which was a bit disappointing. Shane Ferguson has an illness. We were only notified of that this morning so we'll monitor him over the next 12, 24 hours with the possibility of bringing him out on Wednesday."
O'Neill will take charge for the first time since signing a new two-year deal and, with a Euro 2016 qualifying campaign to begin next September, is taking the fixture seriously.
"Between now and the Euros starting we probably have a maximum of four games, staring with this one," O'Neill added. "Given the redevelopment of Windsor Park we're playing most of those games away from home so this will be a very tough test.
"Turkey are a very good team and will be disappointed not to make Brazil so it's a good game for us. The experience is of huge benefit to the younger players - and there are plenty in this squad."