From 1967 to 1999, 22 of 33 defending Super Bowl champions started a future Hall of Famer at quarterback in Week 1. Since then, only one quarterback for a defending champion is even eligible for the Hall of Fame right now (Kurt Warner), but 12 of the past 16 defending champions started a QB who will likely end up in Canton (Tom Brady, Drew Brees, Eli Manning, Peyton Manning, Aaron Rodgers, Ben Roethlisberger and Warner).
So it's very rare for a defending champion to have a questionable quarterback situation going into the season. But that's exactly where the Denver Broncos find themselves, with 2015 seventh-rounder Trevor Siemian being named the Week 1 starter. Only one other champ has kicked off its title defense with a quarterback in only his second NFL season. That team, of course, was also the Broncos. And no other defending champion ever had a starter who had yet to throw a regular-season pass in the NFL.
But which defending champs had the worst Week 1 starters? In compiling the list below, our goal was to judge the quarterback situations based on how they looked at the time, not how they look in retrospect. That's why the 2001 Baltimore Ravens do not make our top five. We think of Elvis Grbac as one of the worst quarterbacks to ever start for a defending champion, but going into that season he actually looked like an excellent free-agent signing by the Ravens.
Grbac had been Kansas City's starter for two years. He was coming off a Pro Bowl selection, back when QBs selected for the Pro Bowl actually went to the Pro Bowl. Grbac threw 28 touchdowns and just 14 interceptions in 2000. Football Outsiders' DYAR (Defense-adjusted Yards Above Replacement) metric ranked him fourth in passing value among all quarterbacks in 2000 and sixth in 1999.
Here are five defending champions with quarterback situations that looked even shakier than the Ravens replacing Trent Dilfer with Grbac.