The 17-year-old centre-half is a rising star at Tannadice, and Sunderland have made two bids for him, with the second, believed to be around £600,000, being accepted by United, who left the player to decide whether to stay or go.
Souttar travelled down to the Stadium of Light last month to have a look round the facilities and meet Sunderland officials.
But having thought over the potential move to Wearside, he has now decided to remain on Tayside.
Source: Sunderland-Mad
Source: FOOTYMAD