Jordan Thorniley is confident the Owls will rectify their defensive problems ahead of the new Championship campaign.
Wednesday signed off their pre-season programme with a 3-1 Hillsborough defeat to La Liga side Villarreal last weekend. Their defending for the opening two goals particularly left a lot to be desired.
The result came off the back of Jos Luhukay's team shipping in two goals against Mansfield Town.
"In pre-season, you have to get back familiar playing with each other again and get your positioning right on the pitch, especially as a defender," Thorniley told The Star.
"If you're positioning is not there, you are going to concede goals.
"I think it will come in time but obviously it is a foundation we need to work on on the training ground."
Although Wednesday produced an encouraging first half showing against Villarreal, their Spanish counterparts cruised to victory after goals either side of half-time from Gerard Moreno, Ramiro Funes Mori and Karl Toko Ekambi.
Follow Dom Howson on twitter
Thorniley said: "Villarreal have been up there in La Liga in the last couple of years so it was a good test for us.
"They are a good team and played some fluent football.
"But I thought we did well and played some good stuff at times. Obviously, we conceded three goals which isn't ideal but I think on the whole we played well.
"We just switched off for a couple of the goals."
The 21-year-old has called on the Owls to improve their defensive focus as they prepare to take on Wigan Athletic in their Championship opener.
"We have to be steady, compact and concentrate all the time," said ex-Everton trainee Thorniley. "I think we will get better as we go on.
"The signs are there we doing alright. We are getting stronger with the more games we play."