The Chiefs defense has been close to or at the bottom of the pile on the NFL for the last two seasons. Kansas City’s defense improved from 32nd to 29th in total defense and lowered its points per game from 25 to 20. But that improvement wasn’t enough as the Chiefs failed to stop the Colts in their playoff game last Sunday. On Tuesday, defensive coordinator Greg Robinson resigned. He said resigning was his idea and after a night to sleep on it, Dick Vermeil agreed to accept the resignation. Robinson said he hoped resigning would make it easier for Vermeil, “What I had hoped was that I had unshackled him from all of his beautiful loyalties and thought about the football team. And he did that.” Tearfully, Vermeil said, “It’s tough to say goodbye to Greg. I’ve watched him coach since he was a kid. I spent hours with him when I was broadcaster and he was a coach and he’d come up to Philadelphia just to spend a day with a so-called genius.” The quest to replace Robinson has already begun. The Chiefs have requested permission to talk with former Chiefs head coach Gunther Cunningham, who currently serves as the Titans linebackers’ coach. Vermeil is also considering promoting Peter Giunta, who used to be the Rams defensive coordinator or Joe Vitt.