Pro Bowl running back Jamaal Charles leaves Chiefs practice with foot injury

Pro Bowl running back Jamaal Charles left midway through the Chiefs' practice Monday with what coach Andy Reid called a strained foot. X-rays were negative.

Charles was participating in an 11-on-11 portion of practice pitting the No. 1 offense against the top defense when he walked off the field and spent a moment speaking with trainers. He climbed into a cart and was driven up a long hillside to the locker room.

Dozens of people watching practice tweeted that Charles had been "carted off the field," and that triggered a rush of speculation about the nature or severity of the injury.

Charles missed nearly an entire season two years ago with a torn ACL in his left knee.