Bortles is expected to bring experience and stability to the backup role behind Goff.
Sean Mannion, who is now an unrestricted free agent, spent the past four seasons as a backup with the Rams. A third-round pick in 2015, Mannion passed for 258 yards, with an interception, in 10 games. Last season, Mannion played the majority of the snaps in the preseason, as Rams coach Sean McVay elected to not play the majority of his starters, including Goff. Mannion struggled in three preseason starts and created uncertainty about his ability to step in if needed.
The Rams also have quarterback Brandon Allen on the roster.
The Jaguars waived Bortles after five tumultuous seasons just hours after signing free-agent quarterback Nick Foles.
Cutting Bortles, who was drafted third overall in 2014 by the Jaguars, was expected after the team benched him for backup Cody Kessler and fired offensive coordinator Nathaniel Hackett on Nov. 26, one day after the team lost at the Buffalo Bills. Bortles threw for 127 yards and a touchdown with two interceptions in that game, one week after throwing for 104 yards in a home loss to the Pittsburgh Steelers.
Bortles, 26, sat out the next three games, played in relief of an injured Kessler in the Jaguars' victory at the Miami Dolphins in Week 16 and started the final game of the season. He threw for 107 yards with an interception in the Week 17 loss at the Houston Texans. Bortles finished his fifth season completing a career-high 60.8 percent of his passes for 2,718 yards and 13 touchdowns with 11 interceptions in 13 games.
Bortles had an up-and-down career with the Jaguars. He set single-season franchise records in passing yards (4,428) and passing touchdowns (35) in his second season, but he followed that with a disastrous 2016. His mechanics -- especially his elongated delivery -- deteriorated. He threw 16 interceptions, including three pick-sixes. He was admittedly somewhat of a mental mess. And the Jaguars won just three games.
The first part of the 2017 season wasn't much better. Bortles had a five-interception practice early in training camp and got pulled from a practice a few days later. Coach Doug Marrone opened up the quarterback job after Bortles' dismal performance in the second preseason game.
But Bortles won the job back, played solidly but not spectacularly for much of the season, was the league's top-rated QB for three weeks in December, then played turnover-free football in three playoff games. He completed 60 percent of his passes for the first time and cut down on his turnovers significantly (16, which was five fewer than his average during his first three seasons).
Bortles' performance in the playoffs -- 594 yards, three TD passes and no turnovers in the Jaguars' run to the AFC Championship Game -- after his improvement in the regular season was what clinched the front office's decision to sign him to a three-year extension worth $54 million with $26.5 million guaranteed.
That move drew heavy criticism from the national media and anonymous league executives. Bortles quieted those critics with a good first month of the 2018 season: He completed 64.7 percent of his passes for 1,095 yards and seven touchdowns with three interceptions. Bortles threw for 376 yards and four touchdowns in a Week 2 victory over the New England Patriots, and he threw for 388 yards and two TDs two weeks later in a win versus the New York Jets.
Bortles' season devolved after that. He threw for a career-high 430 yards but also committed a career-high five turnovers (four interceptions) in a loss at the Kansas City Chiefs, including an interception that bounced off an offensive lineman's helmet. Bortles was benched early in the second half two weeks later after he lost a pair of fumbles, but he regained his starting job before finally losing it after the Buffalo loss.
Bortles is second in Jaguars history in passing yards (17,646) and passing touchdowns (103) in 72 starts, but his maddening inconsistency is making the franchise start over at the position.
Bortles is one of only 15 quarterbacks to surpass 100 touchdown passes (he has 103) since he entered the league in 2014, but he also leads all signal-callers in interceptions (75) and all players in turnovers (94) during that span.
ESPN's Michael DiRocco and Lindsey Thiry contributed to this report.