Reilly's predecessor as GM Europe president, Carl-Peter Forster, quit last November when GM decided not to sell Opel to Canadian supplier Magna International and its Russian-backers. In December, Opel's finance chief, Marco Molinari, left the carmaker to pursue other interests.
It's unclear whether Demant, 59, will retire or take on a technical role at Opel. Demant has been GM Europe's vice president of engineering since 2001 as well as Opel managing director since 2004. He was criticized for staying in the background during the struggle to prevent Opel from following parent GM into bankruptcy last year and has a low-key profile, rarely giving media interviews.
The Frankfurter Allgemeine Zeitung reported on Friday, quoting Opel supervisory board sources, that Reilly will add Demant's role to his duties.
Opel isn't commenting on Demant and has dismissed reports about his future as speculation.
Reilly says the new leadership structure at Opel and sister brand Vauxhall will have new blood and old hands.
“It will be a team that can hit the ground running with our ambitious agenda. They are a great mix of people familiar with the Opel/Vauxhall organization and others who can bring new, innovative opinions and approaches,” Reilly wrote on a blog on GM Europe's Driving Conversations Web site.
Opel's supervisory board meets Friday, Jan. 15 and is likely to approve Reilly's new team.