Sources told NFL Network and ESPN of the move Friday. The Saints were expected to start Jameis Winston -- the No. 2 quarterback on their depth chart -- before they decided to promote Hill. Starter Drew Brees will miss Sunday's game due to a collapsed lung and fractured ribs.
Hill has thrown just 18 passes in 46 career appearances since he joined the Saints as an undrafted free agent in 2017.
The BYU product has been used primarily as a gadget-type player and had a career-high 390 yards from scrimmage and seven touchdowns last season. He has 260 yards from scrimmage and two touchdowns in nine games this season.
Hill has been lined up at quarterback, running back, wide receiver and tight end. He also has returned kicks and punts.
Winston threw 33 touchdown passes, 30 interceptions and led the NFL with 5,109 passing yards last season for the Tampa Bay Buccaneers before he signed with the Saints last off-season.
The former No. 1 overall draft pick completed 6 of 10 passes for 63 yards when he took over for Brees on Sunday when the Saints beat the San Francisco 49ers.
Despite Winston's recent role and his superior experience compared to Hill, the third-stringer has taken all quarterback reps this week with the Saints starters.
The Saints host the Falcons at 1 p.m. EST Sunday at the Mercedes-Benz Superdome in New Orleans. The Falcons have allowed the second-most passing yards per game this season.