Trey Lance or Sam Darnold: 49ers remain undecided on backup QB to Brock Purdy

San Francisco 49ers coach Kyle Shanahan hasn't decided yet on who will be the No. 2 quarterback behind Brock Purdy and said that Sam Darnold and Trey Lance could rotate the job throughout the season.

Lance and Darnold have shared the backup quarterback duties throughout training camp, alternating which one gets the primary work behind Purdy.

The Niners have often kept only two quarterbacks on the initial 53-man roster during Shanahan's first six years in San Francisco but could opt for three this season.

Teams are allowed to designate an emergency third quarterback on game days this season as long as that player is on the 53-man roster — a rule change put in place after the 49ers ran out of healthy QBs in the NFC title game.

"You keep three when you have three," Shanahan said Tuesday. "It’s hard with the 53-man roster. You’d like to keep two so you can get another position somewhere. ... For what happened to us the one time out of 10,000 games or whatever it is, I don’t think people are going to change their rosters because of that. But, if you do have a third one that you don’t want to lose, then that’s what you have to do."

The Niners will likely opt to do that because they want to keep Darnold and Lance on the roster. Shanahan said he would make a decision on the backup before the season opener at Pittsburgh on Sept. 10, but added that it might change depending on matchups and how the two are performing in practice.

Lance started the first exhibition game and played the first half with Darnold coming on and playing the bulk of the second half. The order flipped last week with Darnold coming on for the second drive of the game after Purdy was replaced and playing until late in the third quarter, when Lance came on and finished the game.

Shanahan plans to give Purdy and the first-team offense its most playing time in the exhibition finale on Friday night against the Chargers, but will wait until after practice on Wednesday to determine the order for Lance and Darnold.

Lance hasn't lived up to expectations that were heightened when San Francisco traded three first-round picks to draft him third overall in 2021. He started just four games his first two seasons, replacing an injured Jimmy Garoppolo for two games as a rookie and starting two games last season before going down with a season-ending ankle injury.

Shanahan said he believes Lance has returned as a better quarterback. Although he struggled in the exhibition opener and early last week, he showed positive flashes with two late scoring drives as Shanahan said he has seen progress.

"I think he made a positive out of it because mentally he really saw what he had to improve on just watching other guys go through it," Shanahan said. "It’s been pretty well-documented, but I think he did improve on that stuff before he came back and now improving on it before he came back has allowed him to get a lot better through all those reps."

Darnold was also picked third overall, by the Jets in 2018, but he struggled in his first five seasons with New York and Carolina and is trying to revitalize his career in San Francisco.

"He’s been real consistent in everything," Shanahan said "He didn’t come in the first day just owning it all because you can’t when you don’t have the experience. But each day that he’s done it, he’s gotten better and better and he just looks more and more comfortable in everything he is doing."

In other news, Shanahan said he's not surprised that Defensive Player of the Year Nick Bosa's contract holdout has lasted this long and is not concerned about whether he will be back in time to start the season.

Bosa is seeking a long-term deal to replace the fifth-year option of his rookie contract and could command a deal that is the richest ever for a defensive player.

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With fewer than three weeks before the start of the season, Bosa will have little time to get up to speed once a deal is reached. But Shanahan believes that won't be an issue after Bosa excelled as a rookie despite missing most of camp with an ankle injury.

"It’s different for every player," Shanahan said of the practice time needed. "I have as much confidence with Nick as any player I’ve ever been around. You always want it to be more time. I wish it was three weeks. I wish it was five weeks. Not sure how many weeks it’s going to be, but you always would like more."

Reporting by The Associated Press.