Jonathan Walters looks to be winning his battle to be available for the Republic of Ireland's Euro 2016 opener against Sweden on Monday.
Assistant boss Roy Keane said the Stoke striker trained "fully" on Saturday morning after suffering with Achilles problems over the past week.
"He got through it. It was a decent session for him," said Keane.
Previous injury concerns Robbie Keane, Robbie Brady and James McCarthy also all trained again without any problem.
"It's good for the manager to have all players available for selection," added the Republic assistant boss.
LA Galaxy striker Keane, 35, missed both the warm-up games against the Netherlands and Belarus because of a calf injury, while Everton midfield McCarthy, 25, has been bothered by groin and hamstring problems since the end of the club season.
Norwich's left-sided player Brady sustained a back twinge last weekend while picking his baby daughter out of the path.
Republic given day off on Friday
Republic player of the year Walters had taken only a light part in training on Thursday but, like all of the squad, was given the day off on Friday.
"We decided with the medical staff, we would try to keep as close to how the boys would be preparing, let's say, for club football and with Monday's game in mind, we'll train a couple of days beforehand," said the Republic boss on Friday at his team's training base in Versailles.
"Although we climbed on the bus and went down to the training ground, it was really just a walk.
"The medical staff are saying just leave Jon Walters as he is at this minute and let's see how he is tomorrow, just to see if there was any reaction from yesterday's training."
Sweden opener vital for Republic - Long
Striker Shane Long accepts that Monday's opener is likely to prove a "key game" to the Republic's chances of progressing to the second round.
"If you look at the three games as a whole, I think the Sweden game is a great chance for us to put our stamp on the Euros and really put ourselves in with the best chance of progressing," said the Southampton forward.
For his part, O'Neill acknowledged that the excitement is starting to build within the squad.
"Very much so. It's right upon us," added the manager, whose squad arrived in France on Wednesday.
"When you are coming in on Wednesday, I think you forget the competition actually starts quickly, and the weekend will fly in, I bet you.
After the Group E opener against Sweden at the Stade de France, the Republic face Belgium in Bordeaux on 18 June before taking on Italy in Lille four days later.
|Republic of Ireland's Euro 2016 Group E games|
|Fixture||Venue||Date & time||BBC coverage|
|v Sweden||Paris||13 June, 17:00 BST||BBC TV, BBC Radio 5 live|
|v Belgium||Bordeaux||18 June, 14:00||ITV, BBC Radio 5 live|
|v Italy||Lille||22 June, 20:00||ITV, BBC Radio 5 live|
|Live text commentary on every game on BBC Sport website|