Frankie McAvoy has suffered from the illness himself and missed parts of last season and developed a blood clot in his leg as a result – just as he thought he was getting better.
Recently, North End have been without Tom Barkhuizen who has suffered from Covid, his ashtma also adding complications.
Youngster Lewis Leigh, who featured regularly in pre-season, has also just returned.
Liam Lindsay, Ched Evans and skipper Alan Browne were all absent at the weekend and that is set to continue.
McAvoy said: “We’ve no new cases at the moment which is pleasing, but at we still have Ched Evans, Liam Lindsay and Alan Browne having to self isolate.
“Tom Barkhuizen returned on Monday as did Lewis Leigh to a phased return.
“They both trained on Monday for the first time, it’s better but there will still be some that won’t be anywhere near involved.”
North End’s players are not yet all double jabbed, though the plans are in place to have those done in the next week.
Vaccinations are the choice of the individual and the club are not forcing any of their players to have them.
McAvoy feels in the interest of his players’ safety, they should get the vaccination, and he has made that point to the squad.
He told the Lancashire Post: “I’ve said before, I would encourage everybody – I’ve had Covid myself and was unwell with it – to get double jabbed.
“I know people have got their own personal preferences on wanting to get it or not.
“At the end of the day, having had it and knowing people who have had it, it’s not a nice illness at all. Even when you’re fit and healthy, I’ve seen footballers here who it has knocked for six at times.
“The most important thing for me is that it’s with us and it’s not going away, so we need to protect ourselves as best as we can against getting it.
“At the moment, we’re in a situation where we’re having to isolate players and that will continue to happen but I just think if people get double jabbed, it’s less likely.
“That’s my preference and the guys know that, they know my thoughts on it. I understand that people have their own decisions.
“At the moment there is no word from the powers above saying that everyone needs to be double jabbed. I know there are a lot of managers that have the same stance as myself.
“Who am I to decide? I can only give you my thoughts and opinions on it and at the end of the day, it’s down to everyone else what they want to do.”