The 20-year-old Old Trafford youngster has been away on international duty with England’s under-21s, giving Craig MacGillivray a chance to impress between the sticks.
The boss insisted neither goalkeeper was signed as a No.1 when joining this summer.
Henderson was given the nod on League One’s opening day and has quickly caught the eye with confident displays at Montgomery Waters Meadow.
And Hurst, who welcomed Henderson back into training this week, has confirmed there is no pressure from Jose Mourinho to push Henderson into the fold.
“No they don’t put on any pressure to play him,” said the boss. “I wouldn’t have taken him if that was the case.
“It’s the case of who’s doing the best job and there wasn’t too much between them in pre-season. I just went for Dean and he’d done well.
“But Craig’s certainly done as much as he can do in the couple of games he’s played.”
Meanwhile. Hurst revealed his League One manager of the month nomination was recognition of the whole club’s achievement.
“The only reason you get nominated is because of the players’ performances on the pitch,” added Hurst.
“Added to that the support that the players and I get from the rest of the staff, it’s a massive effort.”
Peterborough boss Grant McCann picked up the award.