Jamaal Charles' Injury, Fantasy Outlooks Following His Week 2 Ankle Sprain

Kansas City Chiefs running back Jamaal Charles could not avoid Week 2's nasty, injury-filled Sunday, going down with an ankle sprain early during his team's matchup with the Denver Broncos.

The official Chiefs Twitter account broke the news after he left the game, originally calling him questionable to return—and eventually out. Chiefs reporter Rachel Santschi later called the injury a sprain, citing head coach Andy Reid.

After the injury, details slowly trickled in throughout the day, but the picture remains incomplete. However, NFL Network's Ian Rapoport later tweeted that an MRI is forthcoming Monday morning—likely with more clarity.

To understand Charles' pending prognosis, let's take a closer look at the anatomy of an ankle sprain, key things to look for after one occurs and what the Chiefs star faces in the days and weeks to come.

Types of Ankle Sprains

A sprain implies a ligament injury. Ligaments are bands of tough tissue that connect one bone to another, serving to stabilize motion at a joint.

Generally speaking, the ankle carries two groups of ligaments. The lower group connects the bones of the lower leg—the tibia and fibula—to the heel and foot. The higher group connects the tibia and fibula to each other.

Low-ankle sprains involve the low group, and high-ankle sprains affect the high group.

Jamaal Charles' Case

Those watching the play resulting in Charles' injury saw the running back leap forward and plant his left foot. At the same time, a defender rolled up onto his lower leg from the side and behind. The replay did not show a clear view of the ankle itself, though, leaving room for uncertainty.

However, the angle and direction at which his leg bent leaves room for some concern for a high-ankle injury rather than the much more common low-ankle sprain.

According to Herbie Teope, the broadcast also initially mentioned some concern for an Achilles injury—an injury that, if present, usually ends a player's season.

Nevertheless, observers could see Charles plantarflex his ankle relatively strongly shortly after the injury occurred. The Achilles transmits the force of the calf muscles to the heel, leading to plantarflexion—or pointing of the toes. As such, plantarflexing the ankle with relative ease—which Charles did—strongly hints against an Achilles rupture.

The fact that Charles jogged off the field and walked easily to the locker room also gives reassurance against a fracture, Achilles tear or severe sprain. CBS' Jason La Canfora gave even more later Sunday evening:

As of now, all signs point toward a mild to moderate low-ankle sprain—especially after The Kansas City Star's Terez A Paylor reported negative X-rays—but the chance of a high-ankle injury is real. The looming MRI will paint a much clearer picture, as while X-rays look primarily at bone injuries, MRIs detail soft tissues such as ligaments.

Follow-Up

If Charles' diagnosis does turn out to be a mild low-ankle sprain, Chiefs fans should expect day-to-day and week-to-week re-evaluations of their star player.

That said, ankle injuries and running backs do not go together well. The position demands quick plants and cuts on essentially every play. As such, an absence of Charles for a week or two should not surprise Chiefs fans.

A more troublesome MRI finding—such as increased signal between the tibia and fibula, indicating a high-ankle sprain—could also lead to missed games, up to and including several weeks.

Once Charles returns to action, athletic trainers will probably add supportive taping to his ankle. The tape helps the ankle remain stable despite the healing—and therefore weaker—ligaments. It also provides some mental reinforcement, so to speak, that the ankle will not suddenly give out—even if it could.

Dr. Dave Siebert is a second-year resident physician at the University of Washington and a member of the Professional Football Writers of America. He plans to pursue fellowship training in Primary Care (non-operative) Sports Medicine.

Follow @DaveMSiebert