The Black Cats are struggling near the bottom of the Championship, and need all the help they can get. Now they have 20-year-old Ejaria to provide them with extra options.
Ejaria, a former Arsenal trainee, will offer a vital presence in midfield for the rest of the season. He is delighted with the move.
"I'm really happy because I've wanted to go out on loan for a while to get regular first-team football under my belt," he told Sunderland's website.
He is the third player signed by Sunderland during the transfer window.