Germany international goalkeeper Ter Stegen has been unable to train since suffering the issue on August 16.
The 22-year-old - signed from Borussia Monchengladbach in the close-season - is now ready to resume playing, although he faces a battle to usurp fellow new recruit Claudio Bravo, who has kept clean sheets in wins over Villarreal and Elche to start the Liga season.
Centre-back Vermaelen, who joined Barca from Arsenal last month, took part in a workout with his team-mates for the first time since completing his move.
The Belgian is still recovering from a hamstring injury he picked up while playing at the World Cup.
"German keeper Marc-Andre ter Stegen was able to train normally for the first time since picking up a back injury on August 15 and the medical services have declared that he is fully recovered," read a statement on Barca's official website.
"Thomas Vermaelen was able to train with his new colleagues for the first time, albeit only for part of a session."
In less positive news, though, third-choice keeper Jordi Masip will be sidelined for four weeks with a fractured finger.