The Norwegian has become known for tinkering his Bluebirds XI and looks set to shuffle his pack once more as they look to bounce back from their 4-2 defeat to Norwich with Manga, who arrived from Lorient on deadline day, at the front of the queue for a start.
While Manga looks set to replace Sean Morrison or Matt Connolly in the heart of defence, left-back Fabio may also have to drop out if he fails to shake off a muscle problem he sustained on Saturday, with Declan John ready to step in.
Winger Craig Noone could also be involved in a matchday squad for the first time this season having recovered from injury while Mats Daehli should return to the 18.
Dimi Konstantopoulos is set to continue in goal for Middlesbrough after replacing Tomas Mejias for Saturday's win at Huddersfield.Aitor Karanka has confirmed the 6ft 5in Greek is now his number one shot-stopper and insists he has every confidence in the 35-year-old, who had previously only appeared in two Capital One Cup fixtures.
Mejias suffered a back injury prior to the weekend victory which ruled him out of contention, but Karanka insists he had already made the decision to promote Konstantopoulos and the positions is now his to lose.
Two-goal hero Grant Leadbitter is fit to play again in Wales despite taking a heavy knock at the weekend and Karanka has no new injury concerns.