• Broncos acquire tight end Vernon Davis from 49ers

SANTA CLARA, Calif.  » Quarterback Colin Kaepernick has been told he won’t start Sunday for the San Francisco 49ers and is being replaced by backup Blaine Gabbert, a person with knowledge of the decision said Monday night.

The person spoke on condition of anonymity to The Associated Press because the decision wasn’t to be discussed publicly. The team had not made a formal announcement, though coach Jim Tomsula offered a pretty good hint earlier in the day "we’re evaluating everyone," on the heels of a 27-6 loss at St. Louis and a second straight game without a touchdown and third in five.

Kaepernick has been benched for his birthday, as he turns 28 on Tuesday. In a strange twist, it was three years ago in November 2012 when Kaepernick was promoted to replace Alex Smith and he wound up leading San Francisco back to the Super Bowl and a three-point loss to Baltimore. Kaepernick made his first career start on Nov. 19, 2012, for former coach Jim Harbaugh.

Former first-round pick Gabbert completed 23 of 28 passes in the preseason — for an 82.1 completion percentage — for 203 yards, one touchdown and no interceptions and a 108.8 passer rating. He has stood by locker mate and friend Kaepernick, and they have regularly eaten lunch together, especially last week when a report said Kaepernick was alone "on an island" in the locker room.

"This whole team sees Kap on an everyday basis, we see him 15 hours a day in meetings," Gabbert said. "Unless those stories are coming from in here they’re false."

Bay Area Sports Guy first reported the change. The quarterback speaks each Wednesday, also the next scheduled availability for Tomsula.

Tomsula had always said Kaepernick was his quarterback and made that commitment almost weekly during San Francisco’s struggles this season — until Monday.

The 49ers coach said every player is being evaluated and he didn’t name his starting quarterback for a home game Sunday against Atlanta.

"We’re evaluating everything right now, we’re in the middle of it right now. I don’t have any comments on any position on our field right now," Tomsula said. "We’re evaluating everyone. I’m not going to have any further comment, I’m just telling you we’re evaluating everyone."

Later Monday, the 49ers traded tight end Vernon Davis to the Denver Broncos for a pair of late-round draft picks.

Kaepernick is taking a seat at least this week for a franchise searching for any possible spark after another dismal day on offense. The Niners are 0-3 in the NFC West. They have their bye week next week.

"It needs a jolt, and needs it from every position," fullback Bruce Miller said. "I know that we can play better at all 11 spots and until we do that and play together as a group, I think it’s fair to say that every position is under review because we’ve got to play together as a group, not as individuals."

Kaepernick has passed for just 286 yards the last two games for the Niners (2-6), raising questions for weeks now whether a big change was needed. Perhaps more than just the quarterback, too.

Tomsula wouldn’t say when a decision would be announced, only that, "We’ll make those decisions when we’ve got those things done at every position, every position … Colin didn’t play good enough, neither did the team, the San Francisco 49ers didn’t play good enough."

Gabbert was impressive in the preseason for San Francisco. Jacksonville selected him 10th overall in the 2011 draft.

"I know where we’re going with this questioning. I’m not going down that road," Tomsula said. "I’ve got a lot of respect for Blaine Gabbert."

The defense has appreciated what Gabbert brings every week on the scout team to prepare the Niners for the upcoming opponent’s quarterback.

"That’s coach’s decision. Every position is under evaluation each and every week. That motivates every guy at every position to go out and work a little bit harder … and can be held accountable," defensive lineman Quinton Dial said, then noted of Gabbert: "He definitely goes about his business as a professional. He shows up, works hard each and every day and gives us a great look on the scout team."

Tomsula said he is comfortable with his coordinators — Geep Chryst on offense and Eric Mangini on defense — going forward. The coach also noted he is meeting weekly with CEO Jed York and general manager Trent Baalke.

"I’m not at a self-doubt place now," Tomsula when asked about his own frame of mind.

Former Australian Rugby League star Jarryd Hayne, waived Saturday, was signed to the practice squad.

Notes: San Francisco signed RB Shaun Draughn to fill a void at the injury-plagued position. Carlos Hyde missed Sunday’s game with a stress fracture in his left foot while Reggie Bush was receiving an MRI exam for his injured left knee that he hurt slipping on concrete out of bounds. "Trying to stay healthy has been an issue this season," he said. Mike Davis also was receiving an MRI exam Monday for what could be a broken hand. …TE Garrett Celek is going through the league’s concussion protocol.