The 33-year-old striker, who missed Friday's 3-0 Group C defeat in Germany with an ankle problem, was not expected to train on Sunday and will have to do so on Monday if he is to stand any chance of winning his 130th senior cap on Tuesday night at the Aviva Stadium.
Interim manager Noel King said: "Robbie is still recovering, hopefully. I don't know whether he will train (on Sunday) - I don't think he will - but hopefully (on Monday), he will do a full stint."
Asked if he expected Keane to be available for the game, King replied: "I am hoping he is fit for selection."
Celtic's Anthony Stokes played the lone striker role at the Rhein Energie Stadium in Cologne and on another night could have emerged with a hat-trick, and he would appear to be the leading candidate for the job once again if Keane did not make it.
King said: "They are all good and looking forward to it. It's good to see them in and added to the squad.
"We will do a little bit of training (on Sunday) afternoon and we will see. There are a few tired legs, a few tired bodies, few tired minds, and there's a few anxious and fit-as-a-fiddle minds as well, so it's a combination of things we have to deal with."