Armstead, Ebukam miss 49ers' chilly practice in Colorado Springs originally appeared on NBC Sports Bayarea
Armstead has not played since Week 4 due to plantar fasciitis in one foot and a hairline fracture of his other ankle.
Ebukam missed the first game of his six-year NFL career last week after sustaining a quadriceps strain in practice. He has also been battling Achilles tendinitis this season.
Cornerback Charvarius Ward was excused from practice Thursday due to a personal matter. Coach Kyle Shanahan said it was nothing bad, and Ward would be available to play Monday night.
Although defensive tackle Javon Kinlaw is eligible to be activated off injured reserve, that will not happen this week.
Kinlaw did not make the trip to the Air Force Academy, where the 49ers are practicing this week. Kinlaw remained back in the Bay Area to continue physical therapy on the knee issue that has limited him to just three games this season.
The 49ers are practicing in the 6,700-feet above sea level to get acclimated to Mexico City, where the 49ers will face the Arizona Cardinals on Monday night.
Estadio Azteca (Aztec Stadium) is situated at 7,200 feet.
However, there will be a significant contrast in the weather conditions where the 49ers are playing compared to where they will play. The 49ers began practice in 20 degrees at the same time it was 74 degrees in Mexico City.
Left tackle Trent Williams and defensive end Nick Bosa did not practice on Thursday. Both players were given rest days and are expected to return to practice on Friday.