Former USC star Sam Darnold has a backup plan with the 49ers

During the San Francisco 49ers’ run to Super Bowl LVIII, Sam Darnold’s one-play-away mentality as a backup quarterback came to life.

In consecutive late-season games, starter Brock Purdy left because of injuries, bringing on Darnold, the former USC star and No. 3 pick by the New York Jets in the 2018 draft.

Now, with the 49ers facing the Kansas City Chiefs on Sunday at Allegiant Stadium, Darnold could be one play away from performing on the NFL’s biggest stage.

“As a backup you have no idea what’s going to happen,” Darnold said. “Obviously, we want Brock to stay healthy and stay on the field. But if my time does come, I’m very confident in myself to be able to go out there and do my job.”

The 49ers learned a hard lesson about the need for a capable backup in last season’s NFC championship game against the Philadelphia Eagles.

Purdy, who in the latter part of the season had ascended to a starting role because of foot injuries suffered by Trey Lance and Jimmy Garoppolo, suffered an elbow injury in the first quarter. Journeyman Josh Johnson replaced Purdy, but Johnson suffered a concussion, forcing Purdy to return with no threat to pass.

The Eagles routed the 49ers, 31-7.

With Purdy’s readiness for the start of the 2023 season questionable, the 49ers signed Darnold to a one-year contract that included $3.5 million in guarantees, according to overthecap.com.

It is Darnold’s third NFL stop.

After playing three seasons for the Jets, Darnold in 2021 was traded to the Carolina Panthers. In 2022, he played the final six games — going 4-2 as the starter — but was not re-signed.

This season for the 49ers, Darnold appeared in 10 games and completed 28 of 46 passes for 297 yards and two touchdowns, with an interception. He started the finale against the Rams as both teams sat starters to rest for the playoffs.

Darnold, 26, has high praise for Purdy — the last player selected in the 2022 draft — his teammates and coaches, and the entire 49ers’ organization.

“It’s awesome to be able to work with a guy like Brock, and really everyone in the building is the same every single day,” Darnold said. “And when you get that consistency from your quarterback and from everyone in the building, it makes your job easier.”

The 49ers offense features multiple star players. Purdy was a finalist for the NFL most valuable player award, which was won by Baltimore Ravens quarterback Lamar Jackson. Running back Christian McCaffrey was the league’s offensive player of the year. Receivers Deebo Samuel and Brandon Aiyuk and tight end George Kittle are other weapons.

Darnold’s main job is to help prepare Purdy and the 49ers defense.

When at home in his apartment, Darnold said he verbally goes through play-calls, breaking the huddle, setting players in motion and visualizing coverages.

“I have my own process and don’t move on with the day until my process is done,” Darnold said. “I had a process when I was a starter, and so I just have a new process now that I’m not getting reps on … practice days.”

In December, Darnold replaced Purdy in a 45-29 victory over the Arizona Cardinals, and in a 33-19 defeat to the Baltimore Ravens.

“It was unfortunate that Brock got hurt a couple times this year,” Darnold said, “but I think it definitely helped my mindset, understanding what it takes to be able to go in mid-game.”

Darnold will be a free agent in February and still regards himself as a capable starter. All of his attention is on Sunday’s game, however, whether he plays or not.

That is the role of a backup.

“There is a little bit of a weird mindset that goes with that,” he said, “with wanting to play football, but also understanding my job is to get Brock ready and get the defense ready to go out there and win a game on Sunday.

“That’s my job and I’m going to do the best I can.”