49ers have quandary at backup quarterback (w/video)

BALTIMORE - Anyone searching for 49ers highlights from their 23-3 loss in the preseason opener Thursday didn’t have to plunge very deep into the footage.

Colin Kaepernick and the first-team offense rolled 66 yards on the opening drive with Kaepernick hitting tight end Vance McDonald on a 17-yard pass and promising rookie runner Carlos Hyde rumbling for 34 yards. The drive set up an easy Phil Dawson field goal that gave the 49ers a 3-0 lead.

After that? Crickets.

Kaepernick gave way to Blaine Gabbert after the first series. The team’s presumed backup quarterback has been sharp in training-camp practices but struggled in game action, a persistent critique of Gabbert during three tough seasons in Jacksonville.

Gabbert played until halftime, completing three of 11 passes and tossing an interception on an under-thrown pass to tight end Derek Carrier. Gabbert had a 1.7 passer rating when he gave way to Josh Johnson at the start of the third quarter.

Gabbert’s emergence this offseason had led to speculation that the 49ers might allow Kaepernick to run more in 2014, something they were reluctant to do last year when Colt McCoy was the top backup. The 49ers traded a sixth-round draft pick to Jacksonville for Gabbert. He’s scheduled to earn $2 million this season.

Johnson was 7-of-9 for 63 yards but couldn’t get the 49ers into scoring position. Former Sacramento State quarterback McLeod Bethel-Thompson was 3-of-7 for 26 yards with an interception.

“I think all the quarterbacks - Blaine and Josh and Mac - are coming out of this thinking there are a few (throws) they want back,” Jim Harbaugh said afterward.

“I think they all did about the same. A couple of good throws and runs and extending the play, and a few they’d like to have back, too,” Harbaugh added.

Gabbert had been the presumed No. 2 quarterback, but Harbaugh indicated that the position is murky at this point.

“I think there are spots up for grabs in the depth area,” Harbaugh said. “Whoever comes along the fastest will win those jobs. I think you can say that about quite a few of our positions on the back end.”

On defense, the 49ers allowed 386 yards against a Ravens team that also pulled its starters after the first series. To be fair, six of the 49ers’ presumptive defensive starters were on the sideline to start the game.

That included players dealing with injuries, such as defensive ends Justin Smith and Ray McDonald, as well as a couple of veterans who are healthy like linebacker Patrick Willis and Aldon Smith.

Perhaps the most promising aspect of the game for the 49ers was Hyde’s play.

Veteran Frank Gore took part in warmups and has been healthy throughout training camp. But at age 31, Gore is likely to see only light work in the summer session.

Instead Hyde started the game. On the third play, he showed why the 49ers used a second-round pick on him when, at 235 pounds, he picked up a nice block from fullback Bruce Miller and bounced to the outside for a 19-yard gain.

Hyde also was treated like a starter. He didn’t play any special teams - despite being the team’s top kick returner in practice - and he was pulled from the game after just two series.

Hyde said he was told Wednesday that he’d get the opening carry of the game. He said he daydreamed about what his first NFL run would be like.

“Will I take it to the house on the first one or will I get stopped for negative yards on the first carry?” Hyde said.