The Minnesota Vikings will probably be without star running back Adrian Peterson for at least another week. Peterson was sent to work out in a swimming pool Monday for continued work on his injured right knee, but Coach Brad Childress said he didn't expect Peterson to be ready for the next game against the New York Giants. "It's hard to say right now. He hasn't been on hard land yet," Childress said. Peterson, who still leads the league by a wide margin with 1,081 yards rushing, was hurt in the third quarter of the Nov. 11 game against Green Bay on a tackle by Packers' cornerback Al Harris that caused his lateral collateral ligament to tear. The LCL is the least critical of the four knee ligaments. Peterson has spent "literally, six to eight hours a day" in the training room since then, Childress said. He'll have to spend at least some time in practice before being cleared for action in a game, so it's likely he won't return until some time in December. "I'd say it's a long shot right now to get back there, but we'll see," said Childress, who added that Peterson had surprised him before. Childress noted that Peterson has begun to get used to wearing a brace on his knee.