Adrian Peterson didn't sleep much Sunday night as he mulled the possibilities. His right knee hadn't swelled, which he knew was a good sign, but it was sore, and he hadn't forgotten the pain that knifed through his leg a few hours earlier at Lambeau Field.
"When it's a knee and you're a running back, you are definitely going to worry," Peterson said Monday. "I was kind of worried, not really knowing what to expect."
Shortly after a series of tests beginning Monday at 9 a.m., however, Peterson found out the relatively good news: His knee had remained mostly intact in an awkward collision with Green Bay cornerback Al Harris in Sunday's 34-0 loss to the Packers. The only damage was a torn lateral collateral ligament, an injury that will sideline him for this Sunday's game against Oakland but not much longer.
Athletic trainer Eric Sugarman said the injury does not require surgery and could heal sufficiently enough for Peterson to play Nov. 25 against the New York Giants. Sugarman emphasized that Peterson "absolutely, without question" will play again this season.
"He's very lucky that this is all he has," Sugarman said. "He's going to be fine."
Peterson dropped to the No. 7 overall pick in last April's draft in part because of his injury- filled college career at Oklahoma. Peterson, however, never had suffered a knee injury before Sunday and admitted the worst of thoughts entered his head Sunday night as he awaited a diagnosis.
"I was just hoping it wasn't my ACL or the MCL," Peterson said of two more significant knee ligaments. "I was just praying it wasn't anything too bad. I'm just thankful [it wasn't]."
Veteran Chester Taylor will start in Peterson's place against the Raiders, and Mewelde Moore also should get more playing time. The Vikings built their offense around Taylor and Peterson this season, but injuries have limited them to playing only five full games as a tandem.
For a moment Sunday, it appeared they wouldn't get together again until next season at the earliest. Late in the third quarter, Peterson caught a screen pass from Brooks Bollinger and dashed to the Packers 26-yard line.
Harris sprang from Peterson's left and dived to the ground, clipping the inside of Peterson's right knee. The force pushed the knee outward, tearing the LCL close to the point where it connects to the fibula.
Peterson reiterated Sunday that he considered it a clean hit -- "There's no rule that says you can't cut," he said. "It's part of the game." -- and coach Brad Childress agreed.
"It just looked like [Harris] was trying to enter and get him to the ground," Childress said. "I didn't think it was a particularly vicious hit."
Sugarman said an MRI exam Monday showed significant trauma to the LCL, but it wasn't clear whether the ligament was fully torn. On a scale of one to three, with three being the most serious, medical officials graded Peterson's injury a "2-plus."
Regardless of the severity, Sugarman said, "it doesn't matter because you treat it the same way." The ligament ultimately will grow scar tissue and reconnect itself, but Peterson can resume playing as soon as he feels comfortable changing directions on his right leg while running full speed.
Peterson had little swelling and good range of motion Monday, and he will begin a rehabilitation period that could return him to practice as early as next week. He might need to wear a custom-made brace, but Peterson said: "If it's going to help me heal, I'll wear it to sleep."
LCL tears are the least serious but also the least common among knee ligament injuries in football. Vikings receiver Robert Ferguson sprained his LCL and MCL when he played for the Packers in 2005, and the combination injury forced him to miss five games.
But he said the LCL injury was mild.
"That's the easiest one to have," Ferguson said. "If you had to choose one [ligament to have injured], it would probably be that one."
Staff writer Judd Zulgad contributed to this report.