TEMPE, Ariz. -- The Arizona Cardinals already were having problems protecting Carson Palmer. Now they must deal with the loss of Jared Veldheer.

The 6-foot-8, 321-pound left tackle is out for the season with a torn triceps, an injury that occurred in the Cardinals' 30-20 loss at Carolina two weekends ago.

Veldheer has been the anchor of the Arizona offensive line since he signed as a free agent in 2014 after spending his first four NFL seasons in Oakland.

Palmer called Veldheer "one of the best tackles in the league for a long time."

"His production, his professionalism, his athleticism, his power, his leadership, it's irreplaceable," Palmer said Wednesday.

Stepping into that considerable void Sunday, when Arizona is home against San Francisco, steps John Wetzel, an imposing figure in his own right at 6-7 and 328 pounds.

But Veldheer has 88 career starts. Wetzel has one, at left guard against the New York Jets on Oct. 17 when Mike Iupati was out with an ankle injury against.

Wetzel, undrafted out of Boston College in 2013, signed a rookie free agent contract with Oakland but was released before the season started. He was on the practice squads of Dallas and Indianapolis before being signed the Cardinals practice squad last Dec. 9. Wetzel made the 53-man Arizona roster as a backup this season.

"I feel ready," he said. "It helps that I started a game already this year and played a little bit in the San Fran game. That helps a lot, just the mental aspect of getting adjusted to the speed of things. I've still got a lot of work to do in practice coming up this week, got to get some technical stuff worked on, but by Sunday I should be pretty good."

Wetzel has appeared in all eight games, mostly on special teams before his stint at guard. He played the entire second half against Carolina at tackle after Veldheer was hurt.

"It's really unfortunate what happened to Jared, you don't want to see that," Wetzel said, "but I'm looking forward to being part of the team, doing a little bit more than I was, just doing what I can to help out, get some wins."

Coach Bruce Arians said he's "very comfortable" with Wetzel's new role.

"That's a more comfortable spot for him (than guard), and he's tough and smart," Arians said. "Will he get beat? Probably now and then. They all do -- Jared did too -- but he'll do fine."

Wetzel agreed tackle is his best position.

"I've played it more, I've got more experience," he said. "Really I only first started playing guard when I was in Dallas due to injuries, played a little bit one preseason game and that's about it."

Palmer voiced confidence in Wetzel.

"Wetz is ready, Wetz is excited," Palmer said. "When I talk about guys being here (during the bye weekend), Wetz was around, watching film, studying, working on his technique. He's a physical specimen, so I don't think he'll be one of those guys that has that kind of deer-in-the-headlights look."

It's a second change on the line this season. Earl Watford is at right guard after Evan Mathis, a free agent signee in the offseason -- was lost for the season with an ankle injury at San Francisco on Oct. 6.

Palmer threw for a season-high 363 yards against Carolina but was sacked a season-worst eight times.

"It was really the two interior guys (Iupati and Watford) who'd been there," Arians said. "So yeah, they've got to protect the quarterback better and then block for the running game. The challenge never changes. They've got to block."

The Cardinals have allowed 25 sacks this season. Only Indianapolis (30) and Cleveland (26) have given up more. Arizona's allowed 60 quarterback hits, fifth-most in the league.

Wednesday was a veteran's day off for Palmer. The 36-year-old quarterback said that his 14 NFL seasons have made him appreciate the extra rest.

"I was a gym rat for so long," he said. "I want every rep and I'm greedy with every rep, but I've learned to understand the importance of recovery and rest and sleep and all those things. I understand how important it is for feeling great Sunday."

Notes: Asked if he was ready to declare defensive back Tyrann Mathieu (shoulder) out for the 49er game, Arians said "not yet." ... Mathieu and cornerback Tharold Simon (ankle) did not practice. ... Wide receiver Larry Fitzgerald (ankle) was among five players that were limited.