Republic of Ireland defender Joey O'Brien was due to undergo a scan on a hamstring injury on Saturday.
The West Ham defender felt the problem during the warm-up to Friday night's 3-0 friendly victory over Latvia and sat out training in Malahide on Saturday morning.
Manager Martin O'Neill said: "He's going for a scan. We are not sure.
"He just felt a little bit last night in the warm-up, so even though there was an opportunity last night to play him, we wouldn't have done so just because there might be some risk, so he is going for a scan later on.
"It's his hamstring. He just felt a little bit sore and it is just precautionary. But he wasn't too bad."
O'Neill reported minor knocks to a couple of other players with midfielder Andy Reid, who was used as a substitute against the Latvians, and defender Sean St Ledger understood to be the men in question.