The midfielder, 29, collapsed on the pitch when playing for Denmark in June.
The implantable cardioverter defibrillator (ICD) device he subsequently had fitted means he is banned from playing in Italy’s Serie A.
“Eriksen reached out to us, and he is now training by himself,” said a spokesperson for OB.
“It’s natural for him since he played here in his youth and lives around the corner. We are very happy to be able to provide training facilities for him.”
Eriksen represented OB from 2005 to 2008 before joining Dutch side Ajax.
After seven years with Tottenham he joined Inter in 2020. The Italian champions have said they are prepared to let him leave the club after the country’s medical authority suspended him from playing in Serie A.