Ian Rapoport of NFL Network reported quarterbacks coach Shane Steichen is expected to call plays, while head coach Anthony Lynn will be "heavily involved" and provide input.
The Chargers are 17th in total offense, averaging 350.6 yards per game, and 14th in offensive efficiency, per Football Outsiders.
Los Angeles will hope a new offensive coordinator can help it get back on track following a 3-5 start.
"This is not an easy decision and definitely not one that I take lightly," Lynn said in a statement. "You win as a team, and you lose as a team. It's never about just one person. At the end of the day, however, I simply felt a change was needed at this time. I want to thank Ken for his years of service to the Chargers organization and wish him nothing but the best moving forward."
To some extent, the move comes across as scapegoating Whisenhunt amid a disappointing year after the Chargers won 12 games and reached the divisional playoffs in 2018. The team is 27th in defensive efficiency, and one could argue that is a bigger reason for the poor record.
The last four games did Whisenhunt few favors, though. He was a holdover from Mike McCoy's staff as well, so it's not entirely surprising he was considered expendable.
One would've thought Melvin Gordon III's return to the team from his prolonged holdout would've been a shot in the arm for the Chargers offense. Instead, Gordon has run for 112 yards and averaged 2.5 yards per carry in his four games.
Los Angeles has averaged 297.5 yards and 16.8 points over that stretch compared to 403.8 and 22.5 through the first four weeks.
It will be up to Whisenhunt's replacement to get Gordon back to his Pro Bowl self or minimize Gordon's role to make Austin Ekeler the primary ball-carrier.