Port Vale assistant manager Mark Grew has been "disappointed" with the form of goalkeepers Stuart Tomlinson and Chris Martin this season.
"Tommo had a long period of keeping clean sheets last year and when Chris got in due to a sending off, he did well," Grew told BBC Radio Stoke.
"It's been frustrating for the goalkeepers and the staff. For me, they've both been disappointing.
"They look at their own performances and they've been disappointed as well."
Grew added: "We've worked hard, we've had long chats and discussed what we need to do. I thought Tommo did well on Saturday."
Vale currently have one of the worst defensive records in League Two, conceding 17 goals in 10 games, plus five more in two cup matches.
Tomlinson started the season as first-choice goalkeeper but was dropped following the 3-2 defeat at AFC Wimbledon at the start of September.
Martin kept Vale's only clean sheet of the campaign in the win at Plymouth but then conceded five times in his next two appearances against Bradford and Shrewsbury and was replaced by Tomlinson for the 1-1 draw at local rivals Crewe on Saturday.
Tomlinson admitted that he has not been pleased with his form and believes the battle to become Vale's regular number one goalkeeper is still wide open.
"It's down to me and Chris to make the manager [Micky Adams] make a decision," he said.
"There's been a lot of chopping and changing, which he's entitled to do. Neither of us have really established who's going to be the number one."
BBC Radio Stoke will have live commentary of Port Vale v Rotherham on 94.6FM from 1500 BST on Saturday, 1 October.