Dion Donohue has recuperated from the glandular fever contracted last summer.
Yet that recovery was too late to save his Fratton Park career.
The 25-year-old has been released by the Blues following an injury-ravaged campaign, consisting of just 13 appearances.
For Donohue, the catalyst can be traced back to a glandular fever diagnosis in July 2018, with pre-season in full flow.
The Welshman failed to feature during the summer friendly schedule, before making an initial reserve comeback in September.
Yet the strength-sapping impact of the virus was severe and, coupled with that crucial pre-season absence from training, Donohue’s body spent the campaign repeatedly breaking down.
A groin injury dictated he didn’t feature following mid-March, culminating with Kenny Jackett declining to activate a 12-month club option.
Donohue said: ‘I hadn’t had muscle injuries before this season. The only thing in the past were shin splints – and that was because I was playing on 3G every week.
‘So this came out of the blue, then it was one thing after another.
‘Glandular fever was a big part of it. I missed out on pre-season and wasn’t fit coming into the campaign, always trying to rush back and playing catch-up.
‘My body was breaking down but, because I wanted to play, I was rushing everything and probably declaring myself fit when I wasn't. Nobody wants to sit on the sidelines.
‘To be honest, I don't know where I got glandular fever from. You can get it through saliva, say sharing my drink, but I don’t know how it happened.
‘I didn’t even know I had it. I was feeling very fatigued, some days sleeping all day and didn’t know what it was.
‘I spoke to the doctor, who ran some blood tests, and I was diagnosed. I was isolated straight away to protect the other players.
‘Afterwards, in an attempt to be as fit as possible, I was doing my own work with the fitness coach and, at times, was literally was on the floor out of it. I couldn’t get up sometimes, it was that bad.
‘My body was still unconditioned for professional football and the challenges of training every day and playing every weekend.’
Despite the glandular fever finally leaving his system approaching the new year, the ramifications wreaked the remainder of his season.
Now Donohue is seeking a fresh start – and pre-season training.
He added: ‘The glandular fever went away with time, there’s nothing the doctors can do, you’ve just got to wait.
‘Now I feel fine, I don’t feel bad at all, I don’t feel fatigued, I’m genuinely over it.
‘It has been nine months now and a good pre-season, wherever I end up, will do me good.’