At times, Peterson carries the ball in the wrong hand, or swings his arms wide trying to get extra yards. Both faults make it easier for defenders to knock the ball loose.
On his fumble Sunday, late in the first quarter, Peterson ran to the left with the ball cradled in his right arm. Linebacker Danny Clark wrested the ball loose, but Vikings tight end Jim Kleinsasser recovered it at the bottom of a multi-player pile that took the officials more than 30 seconds to sort out.
Peterson twisted his left ankle on the play and sat out the rest of the series, which Vikings coach Brad Childress attributed more to the injury than the fumble. After encouragement from quarterback Tarvaris Jackson and other players, a more-careful Peterson broke a 67-yard TD run in the second quarter, which accounted for almost two-thirds of his 103 yards for the day on 21 carries.
"I was just on the sidelines, and the guys were telling me to look at the clock," Peterson said. "We had a lot of time left. 'It's a long game, just be patient, don't think about it, and go out there and play ball.' That's what I did. I went out there, stopped thinking about it, and ran - ran like I normally do."
Said Childress: "I hate to see that ball down on the ground, and he needs to protect it, but, by and large, he didn't change his running style. You see him churning and digging, and I want him to be himself."
With that style, Peterson gained a league-leading 1,760 yards on the ground this season as he became the fifth NFL player to rush for more than 3,000 yards in his first two seasons. With 3,101 yards in 30 career games, Peterson has run for an average of 103.4 yards per game.
But the Vikings expect free safety Brian Dawkins, who forced two key fumbles that led to touchdowns Sunday against Dallas, and other Eagles to try to strip the ball from Peterson.
"I expect him to go after everybody," Childress said. "That's the way they do business."