Bruce Feldman of SI.com reported that Long's fate was sealed at last week's Board of Trustees meeting, which Long flew in for but was not allowed to participate.
Long served as Arkansas' athletic director since 2008 when he took over from legendary figure Frank Broyles. Long was the chairman of the College Football Playoff selection committee from 2014-16 and still serves on the committee. He was athletic director at Pittsburgh before moving to Arkansas.
During his tenure at the school, Long hired Bobby Petrino after his less than year-long stint with the Atlanta Falcons. Petrino was fired four years later after lying about his relationship with a staffer after a motorcycle accident.
Long then hired Bielema from Wisconsin in December 2012 after Bielema had won parts of three consecutive Big Ten championships with the Badgers.
Bielema is 29-32 overall and 11-27 in the SEC over his five seasons at Arkansas. The Razorbacks are just 4-6 overall and 1-5 in the SEC this season.
Bielema would not comment on the status of his athletic director when asked by reporters Wednesday.
"I walked out of a staff meeting about a half hour ago, so things have been standard, as usual," Bielema said on his weekly SEC teleconference call. "People prepped me before I got on the phone call that there might be a question, but I haven't received any official notification. Just a lot of hearsay.
"I get the question, but until I am officially notified in a meeting or hear from people officially, I'm just gathering information. I know this, winning ball games helps everybody, so that's all I'm focused on."
Bielema said he has not talked to Long this week.
"(He's been) awesome, not for me as the head coach, of course he has been, but for our student-athletes," Bielema said. "Everything he stands for, everything he tries to give them on the field, off the field. All the services we provide, and the support we have given. It's been awesome to witness and hopefully continue forward."