Bartra, 26, was the only member of the Borussia Dortmund football team who sustained injuries in the incident.
"There's good news," the team said in a statement. "Central defender Marc Bartra is back in team training exactly 29 days after undergoing an operation on his right hand and wrist following the bomb attack on the Borussia Dortmund team bus."
Bartra was still wearing a cast on his arm.
Police detained two men, one of Iraqi descent, who was later released, and a German-Russian, known only as Sergei W.
While police believe Sergei W. was the one who carried out the attack, authorities claim he borrowed money to buy €78,000 ($84,993) in "put option" shares in the club, options that would greatly appreciate in value if Borussia Dortmund saw a drastic fall in share prices. The police also discovered Sergei W. had insisted on staying in a hotel room that overlooked the crime scene.
All this has led prosecutors to consider him "highly suspicious," yet German broadcasters NDR and WDR as well as German daily Süddeutsche Zeitung report that police have no "explicit evidence" on their suspect.
Sergei W. himself denies all responsibility for the attack.