The 18-year-old made his debut for the Black Cats in May 2018, and will spend the rest of the season with the Mariners.
He has made a total of 10 appearances for Sunderland's first-team.
“We’re delighted to have someone of Bali’s calibre joining us for the final push in the league season," said joint manager Graham Fenton.
“He is very highly-regarded at Sunderland having been regularly involved in the first-team squad over the last two years, and we’d like to thank all the members of staff at Sunderland who have enabled this to happen.
“Bali will give us undoubted real quality and athleticism, and I’m sure he will gain massively from the experience with us across the two-month period.
“We’re looking forward to getting him started.”
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