Adrian Peterson Is Back, but Should Vikings Fans Still Be Concerned?

Arif HasanContributor IIIAugust 23, 2012

KANSAS CITY, MO - OCTOBER 02:  Adrian Peterson #28 of the Minnesota Vikings carries the ball as linebacer Justin Houston #50 of the Kansas City Chiefs defends during the game on October 2, 2011 at Arrowhead Stadium in Kansas City, Missouri.  (Photo by Jamie Squire/Getty Images)
Jamie Squire/Getty Images

Adrian Peterson was cleared to practice in pads a week-and-a-half ago. While initial reports indicated that the Minnesota Vikings were considering playing him in a preseason game against either the San Diego Chargers on Aug. 24 or the Houston Texans a week later, the Vikings have announced that Peterson will not see playing time in either of the contests.

Despite that news, Vikings fans should not be worried about his progress.

There have been no setbacks in his rehab process, according to Leslie Frazier, and the medical staff has been excited about the pace of his recovery.

His Christmas Eve injury against the Washington Redskins provided a depressing final note to an already melancholic season.

Nevertheless, Adrian Peterson will still provide Vikings fans with exciting highlights for a few years to come.

The fact that he hasn't been cleared for full-contact practices shouldn't diminish the hopes of eager supporters; Peterson is physiologically back to normal.

To repair his torn anterior cruciate ligament (ACL) and his medial collateral ligament (MCL), doctors typically recommend bone-to-bone grafts, which repair the torn ligament by taking sections of the kneecap, patellar tendon and tibia and using them to repair the torn ligament.

The injuries to the media and lateral menisci can be healed without surgery, depending on the location of the tear.

Adrian Peterson had the bone graft and is well within the recovery range for his bones and ligaments. Both generally heal within four months and the rest of the process involves making sure that the muscles, habits and reactions are back up to speed.

In the first several weeks after surgery, stress will cause the ligaments to tear or the kneecap to fracture, much like they did for Jerry Rice. After the bones and tendons heal, the larger risk is in the musculature and stress patterns for movement.

Reinjury is possible at this point, but not because the bones or tendons are weak; rather athletes need to make sure they aren't stressing their bodies unnaturally—this is why Cedric Griffin tore his right ACL after returning from surgery to repair his torn left ACL.

To prevent that, Peterson needs to return to his previous strength, balance, lateral agility, muscle memory and instincts. Playing at a high level without returning to their previous levels of fitness will encourage athletes to make movements that they are used to making, but that their body is not prepared to.

Cutting at full speed at subpar strength, for example, exerts different force at different points on the body—spots where the body isn't used to handling stress. A person attempting a similar move at similar strength, but with a lifetime of experience at that strength, will not be in the same danger.

At this point, the medical staff is evaluating Peterson's ability to maintain natural athletic movement when engaged in the normal range of motion for running backs.

Recent advancements in technology have improved the capability for medical staff to test natural movement and balance, but nothing prepares athletes better than live practice.

His introduction into practice was to provide new situations that would allow Peterson to react naturally, but at a slower rate than game speed.

The rule against tackling the star running back was likely not because they felt that contact itself could cause re-injury, but that slower practices would give the training staff the data it needed to see if his range of motion is problematic without moving too quickly.

As practice speed ramps up, so too will the hits. Knowing that the hits are real will force Peterson to cut, spin or otherwise avoid contact with much more force and speed than before.

Good film of practice can provide the training staff with the data it needs to determine whether the halfback has regained agility, balance and proprioception—the sense that allows people to know where their body parts are without looking at them.

His reentry into practice is not likely to cause re-injury, and his restriction from preseason games is not because he has moved backwards in rehabilitation. Instead, it's a way to control the pace of his return to the NFL, which will allow a more careful evaluation of where he's at.

Any injury he sustains from this moment on, even in his knees, would be unrelated to whether he's been rushed back to play because at the end of the day, all medical evaluation is a little incomplete.

Does that mean he'll return to his previous level of play? Evidence suggests that it's not likely that he will within the first year but could in the years following. That doesn't mean he has a nagging problem, but that it will still take a year of gameplay to regain all of the instincts that come with being one of the top running backs.

So as fans counsel caution to protect a nearly $100 million investment or decry the uselessness of playing an injury risk against a weak Indianapolis or Jacksonville squad, remember that the Vikings staff is being more cautious than most teams at this stage in his recovery.

Vikings fans should not be concerned with Peterson's return.