Andres Iniesta is yet to recover from his muscle injury but Gerard Deulofeu, Paco Alcacer, Sergi Roberto, Denis Suarez and Aleix Vidal also appeared in training on Tuesday [10 October] ahead of another busy week for the La Liga leaders.
Ernesto Valverde's side will visit to the new Wanda Metropolitano stadium only four days before a Champions League encounter against Olympiakos at the Nou Camp.
The Barcelona manager has been forced to prepare for the crucial clash against Diego Simeone's side with only five first-team players as the rest of his squad have been away on international duty.
The likes of Argentina pair Lionel Messi and Javier Mascherano and Uruguay striker Luis Suarez still have a World Cup qualifier to play on Tuesday.
Valverde, however, was able to call upon Pique and Ter Stegen during the workout with the Barcelona duo having made an early return from their international commitments.
Pique was unavailable for the Spain's 1-0 victory over Israel due to suspension while the Ter Stegen was rested by Joachim Low during Germany's 5-1 victory over Azerbaijan, with the team already having booked a place in the World Cup before their final group game.
"Ernesto Valverde has begun to recover players back from international duty, with Gerard Piqué - who did not play in Spain's game against Israel - and Marc-André Ter Stegen returning to training on Tuesday morning," Barcelona confirmed in the club website.
"The two first-team players joined Paco Alcácer, Gerard Deulofeu, Sergi Roberto, Aleix Vidal and Denis Suárez at the Ciutat Esportiva along with three Barça B players - Morer, Santi Bueno and Moisés - and five more from the U19 A squad - Collado, Iñaki Peña, Monchu, Chumi and Riqui Puig."
Barcelona are yet to provide any update on the recovery of Iniesta after the captain suffered a hamstring injury during the win over Las Palmas on 1 October.
Iniesta was expected to be back to face Atletico after the club ruled him out for only 10 days but the Spanish midfielder was still unable to train with the rest of available teammates.
Meanwhile, long-term casualties Ousmane Dembele and Rafinha Alcantara also missed the workout as the duo are not expected to return to action until next year.
Barcelona will visit the new Wanda Metropolitano at the top of La Liga table after having claimed seven wins out of seven; leading La Liga by five points ahead of Sevilla and six over Valencia and Atletico Madrid.