The veteran defenseman was told over the weekend that there are potential deals on the table for Penguins general manager Jim Rutherford, and Johnson is involved in the majority of them, sources told The Athletic's Josh Yohe.
While a trade isn't a certainty, Rutherford warned Johnson a deal within the next 48 hours is quite possible, and the GM wanted to keep the blue-liner aware of all possibilities, according to the report.
The Penguins may need to make a move to get under the salary cap ceiling before the season begins. Johnson carries a cap hit of $3.25 million and is on the books for the next four campaigns.
After trading defenseman Olli Maatta to the Chicago Blackhawks in June, Rutherford said he had planned to deal "either Johnson or Maatta."
Pittsburgh signed Johnson to a five-year, $16.25-million contract in free agency on July 1, 2018.
The 32-year-old played every regular-season game for the Penguins last season but managed only 13 points while averaging 19:17 in ice time.