Connor Ogilvie, Louis Thompson and Jay Mingi were among a number affected by the bug, although declared themselves available for duty.
The outcome was a low-key and often lethargic display from Pompey off the back of that pulsating 3-3 draw at Sheffield Wednesday on the first day.
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Cowley told The News: ‘We had a sickness bug in the group, a number couldn’t train on Friday, a number were under the weather today but felt well enough to play.
‘I spoke to a few of them after the game and they felt pretty empty. Sometimes when you have a sickness bug and not been able to eat, it isn't easy to go and play with the energy and intensity that you’d like.
‘Maybe that’s a reason, but really there’s not much we can do about that, you can't control it. We can control some of the other stuff.
‘A lot of them were awful (ill) in the build up. Initially it was a few boys, they all got symptoms at different times, so we knew it was a sickness bug.
‘But I wouldn’t want to overdo that point.’
Pompey created 16 goal-scoring opportunities against Mark Kennedy’s side, of which six were on target, as they struggled to break down well-organised opposition.
The recalled Reeco Hackett had the best chance shortly before half-time as the Blues start the 2022-23 campaign with successive draws.
Cowley added: ‘In possesion we have to keep working and getting that joined-up thinking and connecting the whole team.
‘We were too long, too quickly. We’ve got good players and if we could have worked the ball and got some switches on, we could have got some overloads in wide areas, found better positions in wide areas and then gone from there.
‘We wanted to win the game, we even brought Zak (Swanson) on because we now he gives us a real energy on the overlap.
‘Jay Mingi came on and, out of everyone, suffered the most from the illness, but showed good energy and Dane Scarlett was so sharp and carried a threat.
‘But we weren’t able to find that all-elusive goal.’
A message from the Editor, Mark Waldron
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