Johnson, who rushed for more than 1,750 yards each of the past two years, was injured in the fourth quarter last week of Kansas City's 33-22 loss to Green Bay. Coaches have said he would almost certainly not play this Sunday against Denver.

A Denver television station reported earlier this week that Johnson has a broken foot and is out for the year. The Chiefs have insisted all they know is he has a mid-foot sprain and will probably not play this Sunday.

A news release by the Chiefs said Johnson had "less swelling and pain in his injured right foot."

"His status will be re-evaluated again early next week with further exams and tests. His status for this week is doubtful to out," the statement said. It was signed by Carl Peterson, the Chiefs' president and general manager, and team physician Dr. Jon Browne.

Johnson's long-term loss would possibly be crippling to the Chiefs (4-4), who are tied with San Diego atop the AFC West. His 1,958 yards in his first 16 starts exceeded every other running back in league history and he has scored Kansas City's last 36 touchdowns rushing.

It would also be a tough blow financially to the team because he signed a six-year, $45 million contract in August that made him the highest-paid player in franchise history, with $19 million guaranteed.