We profile the three new call-ups in Paolo Di Canio's squad this afternoon.
Hailing from Middlesbrough, the centre-back was signed from Darlington earlier this season following a successful trial.
He made 10 senior appearances for the Quakers in 2011-12 under the guidance of Craig Liddle, who is now on the Academy staff on Wearside.
Harrison has been a regular in the development squad this season.
The speedy youngster (pictured) can play either on the wing or up front and is a product of Sunderland's Academy system.
After playing for the under-18s while still at school, Mitchell then completed a two-year scholarship and has been a regular in the second string for each of the last two seasons.
David joined the club in summer 2012, completing a dream move to the team he has supported all his life.
Like team-mate Harrison, he began his career at Darlington, making six senior appearances last season.
The left-back has been a regular in the development side this season.