After the death of their Owner and General Manager, the Raiders fired their (pretty good) Head Coach and handed the keys to the franchise over to Reggie McKenzie. He brought in a young upstart defensive coach to be his Head Coach and has slowly (but surely) been pushing out guys that he doesn't like and replacing them with new blood. Year 1 of these types of dramatic power shifts are always ugly, and this one certainly is.
On the other side of the coin, you have the Denver Broncos. I don't know what they're doing or why it's working. They have a good base of young talent, acquired from some great drafts by Brian Xander....who they fired immediately after this year's draft. They've had four different Head Coaches in the last 5 seasons. The only thing they've done right recently is sign Peyton Manning and the guys that Peyton Manning likes to play with (Brandon Stokley, Jacob Tamme, etc.). Apparently, that's enough.
The Broncos should blow the Raiders out tonight, but Thursday games are weird and division games are weird and games in Oakland are weird. This one could be closer than you think.