Ezri Konsa and Nico O'Reilly are doubts for England's Nations League match against the Czech Republic on Tuesday after both trained alone on Monday.
The Arsenal centre-back and Manchester City midfielder were following individualised training programmes at Tottenham's training ground, while the other 22 members of the squad took part in group training as normal.
Tuchel faces selection uncertainty
England head to the Czech capital under pressure to secure a first win of their Nations League campaign after a 3-2 defeat at home to Spain in their opening fixture at Wembley on Saturday.
Thomas Tuchel has said he wants to keep his team largely the same as the one that started against the world champions, but the fitness of Konsa and O'Reilly could force changes.
Both players started against Spain, but their availability for the match at Fortuna Arena remains uncertain. The squad is due to fly to the Czech capital on Monday afternoon, with Tuchel expected to provide an update on his players' availability during his pre-match press conference in Prague later in the evening.
Gittens withdraws from U21 squad
Earlier on Monday, the FA confirmed that Jamie Gittens had withdrawn from the England Under-21s squad and returned to Chelsea with an ankle injury.
The Chelsea winger was substituted in the 39th minute of Friday night's 4-2 Euro U21 qualifying win over Kazakhstan. After the match, Gittens was pictured on crutches, and England U21 head coach Lee Carsley revealed the 22-year-old would return to Cobham for tests on the injury.
