Coach Jim Harbaugh said the plan will be the same when the 49ers host the Denver Broncos on Sunday.
"It's going to be the same plan going into this game," Harbaugh said Friday. "I can't just say the starters are playing this amount or the starters on defense are playing this amount or certain backups are playing this amount. It's more individualized to each player, each position."
Teams generally play their starters longer each week through the first three preseason games then back off in the fourth game.
With his team having practiced with the Ravens in the days leading up to the preseason opener, Harbaugh isn't as pressed to play his starters as he might have been.
That means Gabbert and Johnson will get extended looks as they continue their competition for the backup job.
The 10th overall pick in 2011, Gabbert is listed ahead of Johnson on the depth chart, but is coming off a rough debut with the 49ers. He completed only 3 of 11 passes for 20 yards. He was also intercepted once, drawing criticism from the media and fans.
Harbaugh, however, insisted he likes the progress being made by Gabbert, who was traded to the 49ers in the offseason after three injury-filled seasons with the Jacksonville Jaguars.
"It was a good first step," Harbaugh said. "He's continuing to compete well. I feel good with the way he's coming along."
Still, Harbaugh stopped short of saying the backup job is Gabbert's to lose.
"There's a lot of jobs up for grabs," he said. "Nothing's set in stone. I'm very pleased with the job Blaine Gabbert's doing."
Johnson, a fifth-round draft pick by Tampa Bay in 2008 played at Stanford when Harbaugh coached the Cardinal.
One player who won't be playing at all is running back Marcus Lattimore. The 2013 fourth-round draft pick has been "making gains" according to Harbaugh, but remains on the team's non-football injury list.
Lattimore spent his rookie season on injured reserve after tearing three major ligaments in his left knee in October 2012. He was expected to compete for a backup job behind Frank Gore, but strained a hamstring during offseason workouts.
"He's doing well," Harbaugh said. "There's been gains. That's where we're at. Not quite there yet. He's making gains every day.
Note: Harbaugh took part in an ice-bucket challenge to raise money and awareness for ALS research after being called out by his brother, Ravens coach John Harbaugh. Jim Harbaugh, in turn, issued the challenge to President Barack Obama and former President George W. Bush.