Robbie Keane hopes to ease concerns about his stubbornly sore knee with an exploratory keyhole operation in Los Angeles.
The Ireland skipper has returned to LA and will give Martin O'Neill a heads-up later in the week.
"He thought it might have been a little bit of a knock and of course when that's not going away immediately, then you start getting a bit of a concern," said the Ireland boss.
"He feels as if, at worst, he might just get it 'scoped and have a little look around to see what it is, and in this day and age, that doesn't take too long. He'll let us know what happening in the next couple of days."
Asked whether he would bring Keane as part of his back room team should injury prevent him from taking one of the 23 slots, O'Neill said he would give the notion some thought.
"I think Robbie would be thinking he would want to try to make the 23 first and foremost, and then we will see how things develop after that.
"But he has been very influential in the group, he's been very supportive the whole time he has been here and even when he hasn't started in matches, he's still with the team, so, yes, that is a thought, I must admit."
O'Neill conceded that his plans for Switzerland and Slovakia tonight have been seriously disrupted, partiucarly among his strikers.
"It's been a bit of a disruption, yes of course. For a start, I wanted Kevin Doyle to play - he started the game and I wanted him to play at least for an hour if not the whole game depending on how fit he was and how he was feeling.
"Naturally, it was an opportunity for him. I thought he stated the game quite well and he was obviously unfortunate to get injured, so that was a disruption I wasn't expecting.
"I was probably thinking that Robbie Keane would be involved at some stage or another in one of the two games, and I really thought that Jon Walters would probably be fit as well, so yes, it was a bit of a disruption, but these things happen," said the Ireland boss.