"It sounds like it was a bit of an immature act," Reid said. "I normally don't let those things go by. I'll address that. I've got to see it first and then make sure."
Kelce made the gesture in the fourth quarter of the 29-16 loss to the Broncos, after Denver's Von Miller was penalized for roughing the passer against quarterback Alex Smith. As referee Walt Coleman announced the penalty, Kelce made the gesture.
After the game, Kelce explained on Twitter that the gesture was aimed at Miller for the late hit and not at Coleman.
Kelce then deleted that tweet and replaced it with another.
Sorry for that last tweet... I felt as if I had to clarify my doing, forgot I couldn't express myself on here.— Travis Kelce (@tkelce) December 1, 2014
Reid said Kelce's response was inappropriate.
"Is it an emotional game, and do things happen and do guys' emotions get involved in that when one of their guys gets hit? Yes," Reid said. "You see that week in and week out. It is an emotional game. How you handle that is important. If it's throwing you out of your game or you're doing something that is going to cost you one way or the other, that's not the right thing to do."