Swansea aim to seize on Manchester United's defensive problems to cause a Carabao Cup upset.
United suffered a shock 2-1 defeat at Huddersfield on Saturday -- their first in the Premier League this season -- when the Terriers exposed a hastily-assembled centre-back partnership.
Phil Jones had limped off with the game at 0-0 and his replacement Victor Lindelof was directly responsible for what proved to be the winning goal.
Jones will not feature at the Liberty Stadium on Tuesday, and Eric Bailly's continued absence means that United manager Jose Mourinho has to decide whether to give Lindelof another chance or promote promising teenager Axel Tuanzebe.
"We've looked at the Huddersfield game and I've spoken about that with the players,'' Swansea head coach Paul Clement said ahead of the fourth-round tie.
"I've told them any team can be vulnerable at any moment, and we've got to make sure we do our bit right.
"They can't make massive changes because they've got injury issues.
"But we know that whoever they put on the pitch they're going to be good.''
Swansea have already lost 4-0 at home to United in the Premier League this season.
Clement's side were punished in the closing stages in August when they conceded three times during the final 10 minutes.
Swansea suffered another home defeat on Saturday in losing 2-1 to Leicester.
"I've got the players I have, but the balance is slightly off,'' said Clement, who confirmed Spanish midfielder Roque Mesa will start against United for only the fourth time since his £11 million arrival from Las Palmas.
"We're potentially a little bit heavier in midfield than we would have liked and a little short at the back, particularly at left-back.
"If there is an issue with Martin [Olsson] there, who would be able to step in?
"You'd be asking a player who's not a natural left-back, or you go down into the next level at your club.
"But I've just got to get on with it and maybe then we can address some of the balance issues in January.''