KANSAS CITY, Mo. -- Richard Sherman is expected to undergo an MRI examination on Monday to reveal the extent of an injury to his left calf area that sidelined him late in the first half of the 49ers’ 38-27 loss to the Kansas City Chiefs.

Coach Kyle Shanahan said the 49ers don't know the exact nature of Sherman’s injury. The cornerback sat out of practice Wednesday with what the team described as a heel injury.

"It is the same stuff that was bothering him going into it," Shanahan said. "It was the heel and calf area. They are all connected, lower extremity."

Sherman underwent season-ending surgery last year to repair a torn right Achilles tendon while he was with the Seattle Seahawks. He underwent offseason surgery to remove bone spurs from his left heel.

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Sherman required assistance from two staff members to leave the field at halftime Sunday. He limped under his own power back onto the 49ers’ sideline at the start of the second half and back to the locker room after the game.

After the game, Sherman, who clearly was disappointed, did not speak to reporters as he left the team’s locker room to depart Arrowhead Stadium for the return flight back to the Bay Area.