According to the AP:
"Kansas City running back Jamaal Charles has been carted off the field midway through the first quarter Sunday with a left knee injury.
"...His return was announced as questionable, but the injury appeared significant. It appeared Charles might have hurt himself while planting the leg as he went out of bounds."
Hopefully for his sake—and that of his fantasy owners—he will be back and the injury is minor.
But just in case he is out for any length of time, here are some guys you should quickly snatch up off the waiver wire.