The person spoke on condition of anonymity because the deal has yet to be announced.
Afflalo played for the Nuggets for three seasons before being dealt to Orlando on Aug. 10, 2012, as part of the blockbuster four-team, 12-player deal that also involved Dwight Howard. Afflalo averaged 18 points for the Magic last season.
Fournier is an up-and-coming guard whose minutes increased late in the season after Andre Miller was traded to Washington and Nate Robinson went out with a knee injury. Fournier averaged 8.4 points and 1.5 assists in 2013-14.
The 21-year-old Fournier was taken with the 20th overall pick in 2011.
The deal was first reported by Yahoo! Sports.
Denver is coming off an injury-filled 36-46 season in Brian Shaw's first season in charge, missing the postseason for the first time since 2002-03. The Nuggets were without Danilo Gallinari all season as the versatile forward recovered from his ACL injury. JaVale McGee (leg) played only a handful of games, while J.J. Hickson and Robinson tore ACLs. Ty Lawson, Wilson Chandler and Anthony Randolph also were in and out of the lineup.
The Nuggets have the No. 11 pick in the draft Thursday night, along with a second-round selection (No. 41 overall).