Jude Bellingham has been called up to the England squad for the first time following the withdrawal of James Ward-Prowse and Trent Alexander-Arnold through injury.
The 17-year-old midfielder was originally included in the U21 squad, but will now link up with the senior team ahead of the games against Republic of Ireland, Belgium and Iceland.
Bellingham has impressed since making a summer switch from Birmingham City to Dortmund, featuring in 10 matches, scoring once.
Despite being without Ward-Prowse and Alexander-Arnold, England manager Gareth Southgate is hopeful he will be able to call upon Marcus Rashford.
The striker is scheduled to report for duty on Thursday to allow for further assessment on an injury sustained in Manchester United's 3-1 victory over Everton last Saturday.
The majority of the squad arrived at St. George's Park on Monday with Ben Chilwell, Eric Dier, Harry Kane, Kyle Walker, Joe Gomez, Jordan Henderson and Raheem Sterling due to report on Tuesday.
England face Republic of Ireland at Wembley on Thursday before travelling to Belgium on Sunday and welcoming Iceland on Wednesday to complete UEFA Nations League Group A2.
Sky Sports News reported on Monday that England may have to forfeit their final Nations League group game against Iceland, with UEFA expected to sanction Denmark's fixture with the Icelanders on Sunday.
Currently, the UK Government will not allow any of Iceland's players into the country to play the game if they have been in Denmark - where a new strain of coronavirus has been linked to the country's mink farms.
Elsewhere, England U21 manager Aidy Boothroyd has added Everton duo Ben Godfrey and Tom Davies to his squad, but will be without Norwich defender Max Aarons for the matches against Andorra on Friday and Albania on Tuesday.
Source: Sky Sports