The quarterback switch comes after the Falcons have lost four of five games while scoring more than 20 points just once in that stretch.
After Sunday's 19-16 loss to the Pittsburgh Steelers, Falcons coach Arthur Smith opened the possibility of moving from Mariota to Ridder, saying they would be evaluating every position during the bye week.
Mariota had missed multiple open receivers during the loss to the Steelers, continuing a season-long issue.
The Falcons selected Ridder in the third round of this year's draft after four years as a starter at Cincinnati. The plan all along had been to develop Ridder behind Mariota, who started the first 13 games of the season.
Ridder worked behind Mariota throughout training camp, and while he played a lot in the preseason, he was never in a position to unseat Mariota before the season began.
Once the regular season started, Ridder ran the scout team and would gather players after practice almost every day to get extra repetitions. He also worked with Mariota, asking him questions about anything he saw to help his preparation.
Ridder won 44 games at Cincinnati, the third most in college football history, and never lost at home. But he said he accepted he would be the backup in Atlanta and would learn from it before hopefully becoming the top guy.
That time has arrived.
Mariota has been through this before. In 2019, the Tennessee Titans benched him in favor of Ryan Tannehill. Mariota has talked about that experience often -- what he learned from it and how he handled it.
He signed with Atlanta in March on the same day the Falcons traded Matt Ryan to the Indianapolis Colts. The deal reunited Mariota with Smith, who had been the offensive coordinator for his final season with the Titans.
At the start of the season, it looked like the reunion could work. Mariota managed the offense well and had one of the best games of his career in Week 6, completing 92.9% of his passes for 129 yards and two touchdowns while rushing six times for 50 yards and a touchdown in a 28-14 victory over the San Francisco 49ers, which earned him NFC Offensive Player of the Week honors.
Mariota offered the Falcons' offense an added dimension with his ability to run -- he has rushed a career-high 85 times for 438 yards and four touchdowns -- in their run-heavy offensive scheme.
Over the past month, though, Mariota's performances declined as Atlanta gave him more passing attempts. During their 1-4 stretch, Mariota never completed more than 65% of his passes in a game and twice completed under 55%. He also never threw for more than 186 yards, despite having at least 20 attempts in each contest, while throwing five touchdowns and three interceptions.
This season, Mariota is 184-of-300 for 2,219 yards, 15 touchdowns and 9 interceptions. According to ESPN Stats & Information, Mariota has been off-target on 20.5% of his throws this season, tied with since-benched New York Jets quarterback Zach Wilson for third worst in the NFL. The league average is 15.2%. Receivers have dropped only 2% of his throws.
In college, Ridder was 810-of-1,304 for 10,239 yards, 87 touchdowns and 28 interceptions. He also ran the ball 501 times for 2,180 yards and 28 touchdowns.