Boss Graham Turner says his Shrewsbury side are conceding too many goals and wants to bring in a new defender.
Town have conceded twice in each of the last two games and Turner told BBC Radio Shropshire his side's defending has been poor.
"We are conceding, without a shadow of a doubt, some poor goals, some goals the opposition haven't really had to work hard to get," he said.
"That's something we've got to address and put right."
Turner, whose side travel to Rotherham on Saturday, added: "It's something we've worked at in training and there could be changes in personnel.
"I've tried to bring a loan player in this week, but it's failed because we couldn't agree the financial terms of the loan.
"It's an area we're aware of, concerned with and need to put right."