Republic of Ireland manager Martin O'Neill has described the injury that goalkeeper Rob Elliott suffered during the 2-2 draw with Slovakia as a "cruel" blow.
The Newcastle United stopper appeared to twist his knee while attempting to keep out the visitors' first goal and ended up being replaced by Darren Randolph.
"The injury to Robbie Elliott was upsetting. It was a cruel blow to himself, his club and indeed ourselves," BBC Sport quotes O'Neill as saying.
"We played some nice attractive football, particularly in the first half. There were a lot of substitutions made by both teams and that disrupted things in the second half.
"Overall, there were some good performances. The cohesion we had was a bit surprising given how much we had changed things around for this match."
Elliott is undergoing scans at hospital to establish the extent of his injury.