Doyle, who was making his first international appearance in 18 months, had to be taken off on a stretcher in the 27th minute after suffering a deep gash in his leg following a challenge with Norwich defender Timm Klose.
The Colorado Rapids forward was immediately rushed to hospital for treatment, but initial reports suggest he won't be sidelined for too long according to his manager.
"Our doctor just told me it's a deep cut and they're cleaning it out, but there's nothing broken which is great from our viewpoint," O'Neill confirmed.
"He's going under anaesthetic now to get it stitched up and hopefully everything will be alright."
Asked if there was a chance Doyle could miss the Euros with the injury, O'Neill replied: "No, hopefully the cut doesn't get infected. Nothing's broken and that's the case."
Ireland secured a 1-0 victory over Switzerland at the Aviva Stadium in Dublin thanks to Ciaran Clark's header in the second minute.
Clark latched onto Shane Duffy's flick-on from Robbie Brady's corner to deliver the decisive blow, which he revealed afterwards was a routine they had been working on in training all week.
"We'd worked on that [set-piece routine], we'd been in those positions and I knew there was a chance of Shane Duffy winning headers for us. It was an easy finish," Clark told Setanta Sports.
"We need to be concentrated throughout the whole game. We didn't have as much possession as we would have liked but once we got the goal and sat in we were quite comfortable."