United States international Lynden Gooch was stretchered off with an ankle injury while playing for Sunderland's under-23 side on Monday.
Gooch, 20, appeared to land awkwardly on his left ankle following a challenge in the 27th minute.
Sunderland manager David Moyes came out of the stands to check on Gooch as he was being treated, before he was carried off the pitch.
"It was disappointing for Lynden," reserves coach Andy Welsh told the Sunderland Echo. "We'll have to assess him and see how it is."
- Sunderland AFC (@SunderlandAFC) November 28, 2016
Gooch made his international debut for the U.S. against New Zealand in October and was officially cap-tied in the World Cup qualifying defeat at Costa Rica two weeks ago.
The California native has made nine appearances for Sunderland in the Premier League this season, with four starts, while also appearing in three EFL Cup games.