MARTIN O'NEILL has admitted there are still places up for grabs in his Republic of Ireland team for Sunday's Euro 2016 showdown with Poland.

The 63-year-old Ireland boss has spent the last week keeping his fingers crossed over a series of injury doubts, all the while considering options to plug potential gaps in his starting line-up.

Everton midfielder Darron Gibson, who would have been in contention for Sunday's qualifier at the Aviva Stadium, has already returned to his club after admitting defeat in his battle against a groin problem, although O'Neill received better news on Friday when full-back Stephen Ward and winger James McClean were both able to train in Malahide.

However, the team will not be named until the day of the game, and that means there is still time for men to force their way into his plans.

O'Neill said: "I think there are positions up for grabs, like there have always been since I have come here, and I think any international manager would probably tell you exactly the same.

"He's got an idea that he can formulate a couple of weeks beforehand, but the first time that you really consider it is when you have players at your disposal for the week of the game.

"Of course, we have had one or two players who for one reason or another, generally through injury, haven't really been available for the start of the week, so then you have to formulate different ideas, different plans for the players that you think might participate in the game.

"But overall, there have always been positions up for grabs here."

Ward and McClean have both been struggling with ankle problems and while the Wigan winger has been a regular member of the starting XI under O'Neill, it is perhaps the absence of Burnley left-back Ward which would cause him the greater consternation.

Marc Wilson can and has played at full-back, although has more recently been employed as a central defender by his country, while Ciaran Clark is also left-sided and could play in both positions.

However, there is a school of thought which suggests that any vacancy on the left side of the back four could be filled by Hull winger Robbie Brady, who has operated there in the past for both club and country.

Indeed, he scored twice from that position in November's 4-1 friendly victory over the United States in Dublin, and that has not been lost on his manager.

O'Neill said: "He did very well, really well, scored two goals and from that position on the field, was really excellent."

However, Ward's fitness - he has suffered some irritation from screws used to repair his fractured ankle - and readiness to play will be fully assessed before a final decision is taken.

O'Neill said: "I'll have a word with him now and see how he feels. This was the first bit of work that he's done, but we'll see.

"Fitness is very, very important, but sometimes players can get through on adrenaline. You wouldn't want to be going in with four or five players not having done that much, but Stephen knows himself now. If he thinks he can make it, well that's good news for us."

Poland currently lead Group D by three points from Germany, Scotland and Ireland, and while O'Neill does not necessarily view Sunday's encounter as a must-win affair, he knows the impetus a victory would give his side.

He said: "Naturally, we are at home and the onus is on us to try to get forward and try to win the game, and that's what we are going to try to do.

"But there are a number of games left in the competition. You mentioned the top two places [qualify] automatically - it's a tough old group we are in, but we are going for it."

Celebrations of Ireland's RBS Six Nations Championship victory last weekend are still very much ongoing, and O'Neill is hoping to take a little of that into the game.

He said: "The Irish rugby team has done fantastically well and maybe we could take something from that. They have given us a lead, let's go and try to continue that."