It happened a couple weeks ago. Felger has been writing snippy stuff about Dillon for a while, still trying to defend his 2004 position that Dillon was a locker room cancer. He wrote something fairly inocuous (Dillon being childish by throughing the ball across the field after a long run) but either it was the last straw or something about it hit Dillon the wrong way, and Dillon gave him some major crap about it in the locker room the next day.
Felger first made it out like Dillon attacked him, then toned it down to he felt "threatened." He's been talking about his "altercation" with Dillon on TV every couple of days, trying to bait Dillon into doing something newsworthy that can be used on one of Felger's shows.
Think of it like seventh grade, a grumpy, short-tempered athlete being teased by a dweeb from a position of safety, then crying like a baby and peeing in his pants when he actually has to stand face to face with the guy he's making fun of, then bragging he "went at it."
It's Felger. What more do you need to say?