Sunderland have a lack of quality at centre-back this season.
If Sunderland continue to utilise a system which involves three central defenders then there must be a concern over their lack of quality in defence.
Gus Poyet has played with a 3-5-2 formation since the arrival of Jermain Defoe, as he believes the striker works best in a pair up front, but it could expose one of the weaknesses in the Black Cats' squad.
Although Sunderland have had very few problems with their defending this season, with their offensive play needing more work, they do suffer with a lack of strength in depth at the heart of their defence.
Sunderland's first choice pairing of Wes Brown and John O'Shea are reliable performers, but question marks lie over the quality of Sebastian Coates and Santiago Vergini, the next two central defenders in Poyet's pecking order.
The South American pair have both looked erratic and error-prone at times, but one of them will have to play if Poyet wants to continue going with three at the back.
That could cause further problems for the side, rather than offering a solution to their goalscoring issues and it is a big risk for Sunderland to be taking at this stage of the season.
The Wearsiders are only marginally above the drop zone as things stand and if this tactical tweak from Poyet does not work then the consequences could be severe.