McCaffrey could be out longer on IR

MINNEAPOLIS — Christian McCaffrey’s appointment to the Injured Reserve list could keep him there longer than the minimum four-game absence.

“My understanding is he’s likely to be out six week or potentially more,” NFL Network’s Ian Rapoport reported Sunday morning, a few hours before the 49ers’ road opener at the Minnesota Vikings.

McCaffrey did not accompany the team to Minnesota, according to a team source.

McCaffrey’s Achilles tendinitis was described as “painful” and “frustrating,” thus sidelining him not only for last Monday’s season-opening win against the New York Jets but for at least the next month.

Limited in practice most of the past two weeks, McCaffrey was kept out of Friday’s walk-through session after “his worst day” of pain that’s come on and off. He did not participate in spring workouts, and he only practiced about a week into camp before exiting team drills for four weeks with what initially was called a calf injury.

Hence, missing another four weeks is no guarantee his pain will have subsided. The 49ers’ next three opponents after Minnesota: at the Los Angeles Rams (Sept. 22), vs. the New England Patriots (Sept. 29), vs. the Arizona Cardinals (Oct. 6). McCaffrey would be eligible to come back to visit the Seattle Seahawks on Thursday, Oct. 10, with the next two games coming against the Kansas City Chiefs on Oct. 20 and the Dallas Cowboys on Oct. 27, both at Levi’s Stadium.

“We have to be really smart and understand this is a long year,” 49ers general manager John. Lynch said Friday on KNBR 680-AM. “We need Christian fully healthy and out there and don’t want to compromise anything.”