NFL Network Insider Ian Rapoport reported that the running back wasn't spotted at camp on Tuesday, the first of the three-day session, which is mandatory for all players under contract.
Bell hasn't signed his franchise tender, is therefore not currently under contract and can't be fined for missing mandatory minicamp.
The 25-year-old skipping camp doesn't come as a surprise. Withholding his services is the only leverage Bell has at this stage of contract negotiations. Given that he's coming off groin surgery it was unlikely he would have been a heavy participant.
Rapoport noted negotiations are ongoing and if contract talks ramp up, Bell could show for the end of minicamp.
Sides have until July 15 to work out a new deal or Bell will play 2017 on the $12 million franchise tender.