In concerning scenes, Eriksen collapsed during Denmark's tournament opener against Finland in June and was given CPR before subsequently undergoing successful heart surgery.
The 29-year-old was fitted with an implantable cardioverter defibrillator (ICD), meaning he is unable to play for Inter in Serie A due to not meeting the "requirements of achieving sporting fitness" in Italy.
Eriksen would be allowed to play in other domestic leagues across Europe and, according to reports from BT in Denmark, the midfielder has been using his former club OB's training facilities to improve his fitness.
The former Tottenham man has been working with a personal trainer at OB's Adalen training ground and reportedly took part in numerous drills on Thursday (AEDT).
"We are really happy that Christian Eriksen is keeping in shape right now on our courts," OB's sports director Michael Hemmingsen said.
"We have kept in touch with Christian since he switched from OB, and therefore we are happy that he asked us if he could retrain in Adalen."
Eriksen played youth football for the Danish Superliga side before joining Ajax in 2008, later going on to represent Tottenham and current employers Inter.
Barring one visit to Inter's training ground in early August and a trip to visit his international team-mates, Eriksen has rarely been seen in public since the worrying event against Finland, with his future remaining unclear for the moment.