Denver Broncos quarterback Peyton Manning just didn’t look right at all during the Broncos’ loss to the Kansas City Chiefs Sunday and now we might know why. According to reports this morning, Manning is suffering from a partially torn plantar fascia in his right foot.

ESPN’s Adam Schefter is reporting that Manning has been struggling with plantar fasciitis in his right foot for weeks, but it worsened during the Nov. 8 game at the Indianapolis Colts. According to Schefter, he suffered a partial tear of his plantar fascia during that game.

Some Broncos players also told ESPN that Manning had trouble walking during the week.

Partial tears are incredibly uncomfortable, more so than a full tear. As Yahoo Sports notes, Manning’s brother Eli Manning played the 2009 season with a full-torn plantar fascia.

Manning was benched during the third quarter of the Chiefs game. Head coach Gary Kubiak later blamed himself for putting Manning, 39, out on the field, especially since Manning was listed on the team’s injury reports all week. The team put down shoulder and foot injuries and later added ribs to the reports on Saturday.

At the start of the game, Manning did set the NFL record for passing yards, but that was the only good thing that happened on the field. He only completed five of his 20 pass attempts and threw four interceptions before Kubiak pulled him for Brock Osweiler.

The Broncos lost 29-13, dropping their record to 7-2.