Their call-ups followed the withdrawals of Newcastle United forward Anthony Gordon and keeper Nick Pope through injury and concussion respectively.
Chalobah could get an opportunity for a second senior cap as Crystal Palace's Marc Guehi is big doubt after suffering a foot injury that kept him out of his side's Premier League draw against Brighton at the weekend.
Guehi reported for international duty but will be assessed at the squad's base at Tottenham Hotspur's training ground.
The 26-year-old Chalobah was given his England senior debut by head coach Thomas Tuchel in the friendly against Senegal in June but was not part of the last two squads. Tuchel also gave Chalobah his Chelsea debut in 2021.
England, who have qualified for next year's World Cup finals in North America as group winners, host Serbia at Wembley on Thursday before facing Albania in Tirana on Sunday.
Serbia and Albania are battling for second place.