The 49ers passing attack ranks 30th in yards with Blaine Gabbert as the starting quarterback through three games.

Gabbert, to be sure, hasn’t been very good. He ranks 30th in completion percentage (55.2), 27th in yards (532) and 30th in passer rating (68.6).

The dominant conversation surrounding the 49ers (1-2) offense has revolved around replacing Gabbert in favor of Colin Kaepernick.

That’s unlikely to happen this week when the 49ers play the Cowboys given Chip Kelly said Kaepernick isn’t 100 percent physically making unready to assume the starting job.

Kelly’s avoided blaming the quarterback solely for the struggles in the passing game.

“It’s not always on the quarterback. Sometimes the receivers can run the wrong route,” Kelly said.

“I think sometimes everybody keeps pointing specifically to the quarterback, but it’s not like the offensive line’s playing tremendous, the running back are doing everything, the wide receivers are doing everything and we’re just not getting good quarterback play. I think it’s the entire group offensively. We need to convert.”

Where the 49ers could make immediate changes is at receiver. Their current starting trio of Torrey Smith, Quinton Patton and Jeremy Kerley hasn’t stacked up well against the elite defenses of the Panthers and Seahawks.

At some point, Kelly might consider making changes if his current crop can’t get open consistently enough.

Smith is the established veteran of the group and San Francisco’s fifth-highest paid player. He will stay in the starting lineup given he’s the team’s lone deep threat.

Kerley leads the team with 12 receptions for 114 yards, with seven coming in the season opening win over the Rams. He’s the team’s best option in the slot after Bruce Ellington was lost for the year in the preseason with a hamstring injury.

Patton deflected a Gabbert pass to Seahawks linebacker Bobby Wagner in the third quarter Sunday on a crossing route – and hasn’t proven to be a reliable option opposite Smith to help move the chains. Patton has nine catches for 93 yards in three games, ranking 107th in the NFL.

The 49ers have the third-fewest passing first downs in the league. Both Gabbert and his receivers deserve blame. The offensive line does not. The front five that allowed 53 sacks in 2015, the second-most in the NFL, has tied a league low with two sacks allowed this season.

With the game out of hand late Sunday in Seattle, the 49ers tried new receivers Aaron Burbridge and Rod Streater, who should be in line for bigger roles if Gabbert’s passing options continue to struggle against quality cornerbacks.

Burbridge and Streater played 14 and eight offensive snaps, respectively. Streater had a 19-yard reception in the fourth quarter which was the team’s third-longest play of the day.

“Those guys will continue to get plays as we get more plays on the offensive side of the ball,” Kelly said. “So, they’re developing and coming along in terms of, Burb’s still a rookie, Streater we just got a little while ago, he’s still kind of learning and there’s certain things we know when Streat’s in that he’s a lot more comfortable with than other things that we’re doing.”

Burbridge, the rookie sixth-round pick, is the 49ers’ most physical receiver and does his best work in traffic, evident by his career at Michigan State. While lacking elite physical traits that would stand out at the combine, Burbridge compares more favorably to Anquan Boldin than any of the team’s current receivers.

Streater, 6-foot-3, started 16 games during his first two seasons with the Raiders and has 1,596 career yards receiving. He was acquired in a trade with the Chiefs Sept. 3 for a draft pick. When he gets further acclimated to the playbook, he could see his role increase significantly if the offense continues to struggle.

Kelly indicated both Streater and Burbridge have an opportunity to get more playing time, but that evaluation will be made during the week as much as during games.

“They earn that,” Kelly said. “That’s just by example in terms of what they do from a practice standpoint. If someone’s continuing to stand out in practice, you’re going to make an evaluation every day. You say, ‘Heck of another day by Burb. We need to get him on the field more.’ That’s part of just what this whole process is.”