49ers’ Christian McCaffrey at home in Colorado, focuses on Mexico City

AIR FORCE ACADMEY, Colo. — Christian McCaffrey felt right at home Thursday just 30 minutes up Interstate 25 from his hometown.

Heck, he had a homecoming in the Bay Area just last month when the 49ers traded for the former Stanford star.

All this comfort is about to change.

Sure, there’s sentimental tale surrounding McCaffrey’s homecoming this week, on the 49ers’ break in height adjustment before they play Mexico City Monday night. Once there, at the Estadio Azteca, he is introduced to a backstabbing rivalry whose bragging rights belong to the Arizona Cardinals. And McCaffrey, a lifelong workhorse, could once again be sharing time in the backfield with Elijah Mitchell.

Coach Kyle Shanahan said, “You don’t have to have a fixed opinion about ‘Christian has to get this, Elijah has to have this.’ You might overlap on some things, but it’s like splitting hairs.”

The 49ers teased that aspect last Sunday in their win over the Los Angeles Chargers. Platooning McCaffrey with Mitchell could be her recipe for more rushing excellence, not to mention her ability to receive Jimmy Garoppolo’s fast passes.

“Both can run any run at a high level and both can be in the passing game. It allows them to be a lot fresher,” added Shanahan.

McCaffrey does not disagree.

“When you’re on a team with a lot of different weapons, that happens naturally, which is good,” McCaffrey said. “You want to see boys do plays. When your number is called you have to play the games. That staying fresh through the game and the season is 100 percent good.”

Last Sunday, McCaffrey had more receiving yards (39) than rushing yards (38) while Mitchell finished with 89 yards in the second half in his first action since a Week 1 knee sprain.

Mitchell said after that win over the Chargers he and McCaffrey could become the NFL’s top rushing tandem. At practice on Thursday, they hung out amicably during a warm-up and went over the script with running backs coach Anthony Lynn.

Born just 30 miles north in Castle Rock 26 years ago, McCaffrey on Thursday recalled his childhood starring at Valor Christian High School at Highlands Ranch before finding fame at Stanford.

The 20 degree weather and light snow didn’t bother McCaffrey.

“I love it. It reminds me of my childhood. Obviously, the altitude is why we’re here, so it’s nice to be prepared for that,” McCaffrey said Played a lot of Little League games, it takes me back to the good old days.”