Gabbert will take over as the Niners play at home against theAtlanta Falcons(6-2) on Sunday in the final game before their bye week.
Earlier Monday, coach Jim Tomsula said the team was "evaluating everything," including benching Kaepernick. Also earlier in the day, the 49ers traded tight end Vernon Davis and a 2016 seventh-round pick to the Denver Broncosin return for sixth-round picks in 2016 and 2017.
Kaepernick last week was described in a Fox Sports report as being on "an island" in the Niners locker room. Sources told ESPN's Schefter the usually solitary Kaepernick had stopped wearing his ever-present headphones in the lunchroom and had started engaging with teammates.
Tomsula haddisputed the characterization, as did a few teammates. But that was before their latest loss, a 27-6 defeatSunday at St. Louis.
Kaepernick, who turns 28 on Tuesday, went a fourth straight game without an interception in the loss. But he was also held without a touchdown for the second consecutive game. He threw for 162 yards on 20-for-41 passing and rushed for 28 yards.
Gabbert was re-signed as the backup with a two-year deal in March, after he was the lone 49ers quarterback to throw a fourth-quarter touchdown last season -- a 20-yarder with one minute to play and the Niners trailing 42-10 at the Broncos in Week 7.
Mop-up duty against the Broncos was Gabbert's only action as Kaepernick's understudy last year. Gabbert completed three of seven passes for 38 yards and one touchdown.
Gabbert, a fifth-year veteran, was taken in the first round of the 2011 draft by theJaguarsout of Missouri. This preseason, he completed 23 of 28 passes -- an 82.1 completion percentage -- for 203 yards, one touchdown, no interceptions and a 108.8 passer rating.
The news was earlier reported by bayareasportsguy.com.
In June 2014, the 49ers signed Kaepernick to a six-year contract extension reportedly worth more than $110 million, including a record $61 million guaranteed. The deal tied Kaepernick to the 49ers through the 2020 season and put him among the 10 highest-paid quarterbacks in the NFL.
Since taking over the starting job fromAlex Smithmidway through the 2011 season, Kaepernick had led the 49ers to their first Super Bowl in 18 years after the 2012 season -- they lost by three points to Baltimore -- and to the NFC title game after the 2013 season. In that game, the 49ers lost to the eventual Super Bowl championSeattle Seahawks.
Information from ESPN's Paul Gutierrez and The Associated Press was used in this report.
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