Teenage midfielder Lewis Miley, 18, is set to miss Newcastle's pre-season training with a broken metatarsal.
Miley, who impressed for Newcastle in the Premier League last season and made 17 appearances, is expected to be out for around 12 weeks.
That means Miley - who also suffered a back injury near the end of the 2023-24 campaign - is likely to miss the beginning of the league season.
Newcastle's first league game, at home against Southampton, takes place on 17 August, which is in just under seven weeks' time.
Miley will miss all of Newcastle's pre-season action, including July's tour of Japan.