Young Sunderland winger Tommy Watson is set to miss the next two months with knee and ankle injuries.
Watson, 18, has been part of Regis Le Bris' first-team squad this season, and he has started the last five games.
He scored his first two senior goals in the win over Stoke City last Saturday, but he went off in the first half of the midweek draw with Bristol City.
Watson got injured in a tackle with Robins defender Luke McNally that forced the teenager to limp off.
"It should be two months for him to recover properly," head coach Le Bris told BBC Radio Newcastle.