Smith, who went down without being touched in the third quarter, will undergo an MRI examination today. Owner Jerry Jones said there was no sign of structural damage. Smith, who could walk afterward, told coach Barry Switzer he does not believe the injury is serious.
Donaldson, heart of the offensive line, will miss the rest of the season.
"Ray is the big reason we are where we are," left guard Nate Newton said of Donaldson, a 1980 draft pick of the Baltimore Colts. "We're going to miss him."
The injuries muted that joy that comes from ending Kansas City's seven-game win streak and made the post-Thanksgiving break -- the Cowboys do not play again until Dec. 3 -- more important to the team.
"I'm beat up; we're all beat up," quarterback Troy Aikman said. "We can all use the time off."
In a five-day span, the Cowboys defeated two AFC powers -- Oakland and Kansas City -- by a combined score of 58-33.
The two victories followed the crushing loss to San Francisco. How the Cowboys went from ineffective against San Francisco to dominating against two AFC powers can be explained in one word: Turnovers.
Against San Francisco, the Cowboys had four turnovers without taking the ball from the 49ers. In the last two games, the Cowboys are plus-three turnovers: four takeaways and one giveaway.
The Chiefs, like Dallas now 10-2, committed the lone turnover in this game. It was significant.
Trailing 21-12 early in the fourth quarter, the Chiefs had second down at the Cowboys' 15. Chiefs quarterback Steve Bono, facing a blitz, rolled out to his right.
Bono never saw defensive end Tony Tolbert. He separated Bono from the ball, and linebacker Darrin Smith returned the fumble 63 yards to the Chiefs' 4. It resulted in a game-icing field goal.
"They made one mistake," Switzer said. "They hadn't made any in a lot of games. We'll take it."
One unusual fact said much about this game. In the first 24 minutes, the Cowboys had more points (14) than the Chiefs had yards (10). On their first two possessions, the Cowboys ran roughshod over Kansas City's defense to build a 14-0 lead.
Smith ran six times for 35 yards on the opening 11-play series. He scored on a 15-yard burst through the middle.
Then Aikman connected with Michael Irvin, who made a one-handed grab of a 33-yard TD.
"Dallas was clearly the better team," Chiefs coach Marty Schottenheimer said. "We couldn't stop their offense. When Aikman gets his rhythm going, he's hard to disrupt. Dallas is a