Bears coach Matt Nagy made the switch to Foles after a Trubisky interception helped the injury-ravaged Falcons build a 16-point lead.
Trubisky went 13-of-22 for 128 yards, one touchdown and one interception (71.8 passer rating). The Bears were an ineffective 1-of-8 on third down, with several of Trubisky's downfield passes being off the mark. Trubisky overthrew a wide-open Anthony Miller on what would have been a touchdown completion before halftime.
Foles, 31, promptly moved the Bears' offense downfield, but the drive ended when Falcons cornerback Darqueze Dennard wrestled a ball away from Chicago wide receiver Allen Robinson in the end zone. The official initially ruled the play a touchdown for the Bears but later reversed the call to an interception for Atlanta and a touchback.
Nagy announced on Sept. 6 that Trubisky won the starting job over Foles in training camp.
"This was going be a fair battle for both of these guys," Nagy said at time of the decision. "Both these guys were really battling their tail off every single day.
"In the end, Mitch won the job, and I think that's very important for him, for us, for everybody to understand that he worked really hard to get to this point."
Trubisky, whom Chicago selected second overall in the 2017 NFL draft, ahead of Patrick Mahomes and Deshaun Watson, led Chicago to a 2-0 start in 2020. The 26-year-old quarterback rallied the Bears against the Lions in Week 1 when he fired three fourth-quarter touchdown passes to complete a 27-23 comeback win. Trubisky was largely ineffective for the first three quarters at Ford Field before the late heroics.
Last Sunday, Trubisky completed 18 of 28 pass attempts for 190 yards, two touchdowns and two interceptions as Chicago hung on to beat the New York Giants 17-13.
In 2018, Nagy's first season as head coach, the Bears went 12-4 as Trubisky passed for 3,223 yards and 24 touchdowns with 12 interceptions and rushed for 421 yards and three scores. Trubisky, while playing much of last season with a shoulder injury that required surgery in January, ranked 28th in the NFL in Total QBR (39.4), tied for 27th in touchdown passes (17), 21st in passing yards (3,138), 32nd in yards gained per pass attempt (6.1) and 28th in traditional quarterback rating (83.0) as the Bears finished 8-8.
Chicago traded for Foles -- the MVP of Super Bowl LII while with the Philadelphia Eagles -- at the onset of the new league year. The Bears later declined Trubisky's fifth-year option and announced an open quarterback competition in training camp.