Harper was in sparkling form for the Magpies, and had even caught the eye of England boss Steve McClaren before Allardyce decided to reinstall Shay Given between the posts for the trip to Manchester City.
Srnicek told the Evening Chronicle: "This is good for the manager, because he has two very good goalkeepers.
"He has no worries in case anything happens to one of his goalkeepers - they both can do the job.
"For the manager it's a fantastic situation, but for the goalkeepers it's not that good. Obviously, if you do well, you still might lose your place in the team, like Stevie.
"When a new manager comes in he doesn't really have any preference, but obviously things happen in football.
"I was in the same position as Stevie, and I know how he feels."