By Daniel Chavkin The tight end has played in every game this year. Just a day before the AFC championship game, the Chiefs are dealing with an unexpected injury. Kansas City is already dealing with Patrick Mahomes’ sprained ankle, and now star tight end Travis Kelce must alleviate a late injury. The team listed Kelce as questionable with a back injury after he practiced fully throughout the week. CBS announced Jim Nantz, who is broadcasting the Farmers Insurance Open remotely from Kansas City, said on the golf broadcast that he was told Kelce tweaked his back during practice on Friday. It’s h…