SANTA CLARA >> Fred Warner made it to the field Friday but was listed as questionable to face the Arizona Cardinals in Week 5.

Warner missed the second half of last week’s 30-13 win over the New England Patriots and hasn’t practiced this week due to an ankle injury. He was there on the field for the beginning of practice Thursday but did not participate.

Those who will not face the Cardinals Sunday are defensive lineman Yetur Gross-Matos (knee) and linebacker Demetrius Flannigan-Fowles (ankle). Wide receiver Chris Conley was doubtful with an oblique injury. Listed as questionable along with Warner were tight end George Kittle (ribs), cornerback Isaac Yiadom (thigh), wide receiver Jacob Cowing (shoulder) and defensive tackle Kalia Davis (knee).

Warner was on the field with his position group during the brief media window, a practice that is without pads and typically includes red zone work in a short session. Warner has been walking without a limp or protective boot both after the Patriots game and during the week.

Also on hand was Kittle, who at one point during drills made a leaping catch at full extension on a short pass into the end zone from Brock Purdy.

What will the 49ers do at linebacker if Warner is out?

“It’s a secret,” 49ers coach Kyle Shanahan said.

The last time Warner missed a game was Dec. 5, 2021, a 23-20 road loss to the Seattle Seahawks. Since that day, Warner has played in 52 consecutive games, including the postseason.

The quarterback for Seattle that day was Russell Wilson, and this time it’s a roughly similar challenge in Arizona quarterback Kyler Murray, given his ability to create with his feet and strike downfield with his arm.

With Dre Greenlaw also out for that Seattle game, the 49ers played almost exclusively in a nickel defense with five defensive backs and two linebackers, with Azeez Al-Shaair and Flannigan-Fowles as the strong and weak-side linebackers.

With Flannigan-Fowles out this time, available linebackers in the event of Warner’s absence are De’Vondre Campbell, Dee Winters, Jalen Graham and rookie Tatum Bethune. Greenlaw remains on injured reserve and isn’t likely to return until midseason, at the earliest, while rehabbing a torn Achilles.

Campbell’s play has been uneven, particularly while defending the pass. Winters has had an ankle injury dating to the exhibition finale. Graham was a 49ers seventh-round pick in 2023 and played sparingly. He was released at the cutdown to 53 and signed to the practice squad of the Washington Commanders before the 49ers brought him back this week.

Bethune, a seventh-round draft pick from Florida State, has played in three games with just four defensive snaps, playing 43 snaps on special teams. General manager John Lynch, on his weekly appearance on KNBR-680 on Friday morning, floated the idea of Bethune getting some time as a defensive signal caller.

“A little bit through training camp we saw Tatum have the makeup of a guy who could be a signal caller because they are the ones with the coach in their ear,” Lynch said. “Tatum is that kind of guy. He can grab a huddle, he can communicate, and the guy is a tackling machine.”

Shanahan, while unwilling to detail the 49ers’ plans, said Bethune has progressed nicely as part of what has been a strong rookie class through four games.

“He’s been good, done a good job as backup (middle) linebacker, backup during the preseason, runs the huddle well,” Shanahan said. “He’s been there throughout the week with Fred not being able to practice much. Where he’s needed, he’ll be ready.”

Bethune (6-foot-1, 230 pounds), said he’s been getting himself ready for an opportunity whenever it comes.

“I always feel ready because of the preparation,” Bethune said. “Whatever happens, if Fred’s out or anybody else in the linebacker room is out, my preparation will have me ready each game. Just living the dream. This is something I’ve prayed for, something I’ve always wanted.”

Bethune said he’s been soaking up the knowledge through organized team activities, minicamps, training camp and now the regular season.

“My first week just being in the room with Fred and the rest of the linebackers, I learned way more than I did in college,” Bethune said. “I’m just having fun right now.”

If the 49ers choose to play with five defensive backs as they did in 2021 when Warner was hurt, they could choose to use three safeties on some alignments with Talanoa Hufanga and rookie Malik Mustapha playing along with Ji’Ayir Brown.

Hufanga played for the first time since tearing an ACL last season in Week 3 against the Rams and missed the New England game with an ankle injury. Both Hufanga and Mustapha, who played all 64 snaps against the Patriots, have the capability to play near the line of scrimmage in roles similar to a linebacker.

The only linebacker available on the practice squad is DaShaun White.

RETURN POSSIBILITIES >> Since Cowing left last week’s game with a shoulder injury, necessitating the use of fullback Kyle Juszczyk as a punt return specialist, Shanahan said it’s possible Trent Taylor could be promoted from the practice squad against Arizona.

“There’s a chance. Trent’s an option, Juice is an option, Ronnie Bell’s an option,” Shanahan said.

Taylor is by far the most experienced return specialist on the roster with 112 returns for 1,051 yards and a 9.4 average in 78 games.

Quick hits

• Linebacker Patrick Willis, a 2024 inductee into the Pro Football Hall of Fame, will receive his Hall of Fame ring Sunday during a halftime ceremony. The 49ers will also recognize longtime photographer Michael Zagaris, the team’s official photographer since 1973.

• Davis, who originally was thought to be out until midseason following knee surgery at the end of training camp, will likely come off injured reserve and be active. He will lend depth at defensive tackle. Jordan Elliott, who didn’t finish the New England game due to a knee injury, was taken off the injury list Friday. He’ll be involved in the interior rotation that would include Maliek Collins and Kevin Givens.

• Running back Jordan Mason, the NFL’s second-leading rusher with 447 yards, has 911 career yards — 89 shy of 1,000. If Mason were to break 100 yards against Arizona, he’d be the first in franchise history to gain 100 or more in four of the first five games of a season.