The fired chief executive of the beleaguered Market Basket supermarket chain is offering to return as negotiations continue over his offer to buy the company.

The offer from Arthur T. Demoulas comes as employees who walked off their jobs to support him face a deadline Monday to return to work or risk being replaced.

Demoulas offered on Sunday to take control of the business while he continues negotiating to buy the company from rival family members.

The company's board of directors, however, reaffirmed its support for two co-chief executives who were appointed to replace Demoulas.

Hundreds of warehouse workers and drivers refused to make deliveries to protest Demoulas' firing, leaving store shelves bare.

The grocery chain has 71 stores in Massachusetts, New Hampshire and Maine.