General manager John Paxson did not immediately return a phone call from The Associated Press.
The new deal was reported earlier by the Chicago Tribune, Chicago Sun-Times and ESPN.com, which said the contract would include $71 million in guaranteed money.
Deng averaged 17 points and 6.3 rebounds last season, while shooting 47.9 percent. That marked a drop from 2006-07, when he scored 18 points a game with 7.1 rebounds, while making 51.7 percent of his shots. Deng had rejected a five-year contract extension last October that was worth $57.5 million.
A four-year pro out of Duke, the 6-foot-9 Deng has career averages of 15.6 points and 6.4 rebounds.
After three straight playoff appearances and a trip to the Eastern Conference semifinals, the Bulls faltered in 2007-08, finishing 33-49 in a season that saw both head coach Scott Skiles and interim coach Jim Boylan lose their jobs.
The Bulls are hoping Deng will be a big part of their future along with Derrick Rose, a guard out of Memphis selected by Chicago with the No. 1 pick in last month's draft.
Guard Ben Gordon, who rejected a five-year, $50 million contract before last season, also is a restricted free agent.