Red Bull Salzburg coach Marco Rose is interesting both Schalke and Wolfsburg with the former keen on an answer in the next two weeks, according to respected German publication Kicker.
The 42-year-old has been in charge of the Austrian champions since 2017, leading them to last season’s league title.
His side impressed in both of their wins over Celtic in the Europa League earlier this campaign, playing exciting, expansive football.
Earlier this month his odds to become the new boss at Parkhead were slashed significantly.
He is contracted to Salzburg until 2020 but he has talked about a new challenge.
He told Sky Sport Austria, he said: “I think it’s not so often in your career, that you have a lot of requests and then you have a lot of options.
“I know what I owe the club, and yet at some point it’s about my personal situation, about goals, about new challenges, and about making a decision.”
Celtic now face competition from Schalke and Wolsfburg. The former, Bundesliga giants, are in a similar situation as the Hoops with an interim boss in charge until the end of the season, while Bruno Labbadia’s contract at Wolfsburg expires in June.