Nigel Clough fears he could be without his preferred centre-back partnership when Burton Albion visit the Stadium of Light on Tuesday night.
Captain Jake Buxton is struggling after the 3-1 win over Barnsley on Saturday, a result that served as a major boost to Sunderland's own automatic promotion ambitions.
His partner Kyle McFadzean has been suffering from illness and is also a doubt.
The pair have been vital players in Burton's recent upturn in form, the Brewers scoring ten goals in their last three league games; emphatic wins over Blackpool, Accrington Stanley and Barnsley.
Scottish winger David Templeton, lively in Sunderland's 2-1 defeat at the Pirelli Stadium earlier this season, has been ruled out with a knee problem.
"There is no progress for David Templeton at the moment," Clough said.
"Jake [Buxton] took a couple of knocks on Saturday so we will have to see how he is. We have had a bit of illness in the camp with Kyle McFadzean and Will Miller as well so they are the immediate doubts.”
Burton are one of only two sides to beat Sunderland in the league this season, and with their recent form Clough says there are more confident than ever.
He also praised the Black Cats for the resilience they have shown throughout the current campaign.
"The fact that they have only lost two games all season shows their strength in this league and how resilient they are.
"We are more confident than at any other time in the season.”
Sunderland will move back into the automatic promotion places should they avoid defeat against Clough's side.