He told the Scunthorpe Telegraph: "To expect us to get automatic promotion again this season is a big ask, because there are a lot of clubs in this division throwing money at it.
"But being a realist, I would say I will be very disappointed if we do not finish in the play-off positions."
Wharton is easing back into his daily routine at Glanford Park since his heart attack in March, and hopes to be back at the helm at the start of the season.