49ers Notebook: Shanahan on Cardinals’ QB uncertainty, Williams tipping plays, Colorado weather; Lynch on Ndamukong Suh interest

The San Francisco 49ers are holding their three practices this week at the United States Air Force Academy in Colorado Springs, about an hour south of Denver, to get acclimated to the altitude. On Sunday, the team will travel to Mexico City for Monday night's game against the Arizona Cardinals at Estadio Azteca.

Which quarterback will the 49ers defense face when they take the field? No one is really sure. Both Cardinals quarterbacks are day-to-day with injuries. Kyler Murray is dealing with a hamstring injury that kept him out this past weekend against the Los Angeles Rams, while McCoy is working through a knee injury suffered in that game.

Both quarterbacks practiced today, but were limited, and the 49ers are preparing to face either.

"They're still going to run a similar offense with both, so, schematically, you've got to be ready," head coach Kyle Shanahan said after today's practice. "There's definitely some different skill sets and stuff, but we saw both last year. Our defense knows, from going against both of them, they're both a problem, and you've got to be ready for both."

Concern over Trent Williams tipping plays?

There has been some speculation that left tackle Trent Williams might be tipping plays at the line of scrimmage. The theory is that opposing defenses might better understand what is coming based on the offensive lineman's stance.

A reporter asked Shanahan if there was any concern on the 49ers' part.

"It definitely would be a big deal [if true], but I don't study your viral videos ... or whoever's," Shanahan said. "We're pretty good with Trent."

Change of plans due to weather?

It was under 30 degrees at practice in Colorado Springs today. It figures to be colder tomorrow, with a chance of snow falling overnight. If the outdoor practice field is covered with snow in the morning, Shanahan and the 49ers will move practice indoors. Otherwise, the team will continue practicing outdoors despite the frigid weather.

Any change of plans will be based entirely on safety.

"We're not going to go practice (indoors) on turf because we're cold," Shanahan said. "We're going to go practice on turf [if] the field's not safe."

McCaffrey feeling good

One player who isn't having a problem adjusting to the cold weather in Colorado Springs is running back Christian McCaffrey, who played high school football at nearby Valor Christian High School in Highlands Ranch.

"It feels great, yeah," McCaffrey told reporters. "It feels like home. It is home. ... I love it. It kind of reminds me of my childhood. ... I've played in a lot of games in that kind of weather in high school and little league, so it definitely brings me back to the good old days."

McCaffrey added, "I had track meets here in high school. Even the air is familiar, so when you land on the plane, it brings you back. It is a little bit surreal, but at the end of the day, it's kind of a business trip."

Ndamukong Suh interest

The Philadelphia Eagles added veteran defensive tackle Ndamukong Suh today. Some wondered if the 49ers might have been interested, given the injuries along the defensive line. Against the Los Angeles Chargers, just one of the four starters—Nick Bosa—was available. The unit was without Arik Armstead, Javon Kinlaw, and Samson Ebukam. Armstead and Kinlaw have missed significant time.

Shanahan has already ruled out Kinlaw for Monday. The defensive tackle remains on injured reserve due to a setback in his reconstructed knee. He is eligible to return but did not even travel with the team this week.

Armstead, who has not played since Week 4 due to foot and ankle injuries, did not practice this afternoon. It seems unlikely he will return against the Cardinals.

Did San Francisco even consider Suh? Shanahan indicated that there might have been at least some interest.

"I know that [general manager] John [Lynch] looked into all those guys, so I'm sure he would have talked to him," Shanahan said.

This afternoon on KNBR, Lynch confirmed the 49ers had expressed some interest in the defensive lineman. It just never came together.

"We talked to him last year, and we talked to him earlier this year, and it just never came to fruition," Lynch said on the Tolbert & Copes show. "I think, ultimately, it sounds like he really sought the Eagles as a place he wanted to be, and you can't get them all. He's a good football player who's on the backend of his career, but I'm sure he'll help them, and a good pickup for the Eagles."