Player performance levels vary from season to season. The term "sophomore slump" applies to declines from a player's first to second season, but it also implies there are special challenges associated with transitioning to a second season.

This sounds like fiction to me.

Yes, NFL defensive coordinators will be better prepared for Russell Wilson, Andrew Luck and Robert Griffin III in 2013 than they were when those quarterbacks were rookies in 2012. Wilson, Luck and Griffin should also be better prepared for NFL defenses.

"I've always felt like the most improvement you can make is from Year 1 to Year 2, much like a college freshman who the most improvement he can make in an entire one year of college football is going from Year 1, freshman year, to his sophomore year," San Francisco 49ers coach Jim Harbaugh said last offseason.

Harbaugh then specifically applied the same thinking to NFL players.

"Like a pro football player going from his rookie season to his second season, there’s a window there that will never come again that you have a chance at making your biggest strides," Harbaugh said.

Harbaugh's comments came to mind immediately when watching Ben Roethlisberger and Brian Dawkins discuss in the video above what Luck, Wilson and Griffin must do to avoid falling off in their second seasons.

Players sometimes decline from one season to the next, especially when they are coming off a particularly outstanding season. It's tough to be great every year. However, we don't talk about junior or senior slumps when players decline in their third or fourth seasons. Sophomore slumps sound overrated to me.

Reducing Sam Bradford's 2011 struggles to a "sophomore slump" would ignore a long list of reasons for his decline that were totally unrelated to a player transitioning to a second season. The St. Louis Rams changed offensive systems. They suffered through more injuries than usual. Bradford himself was injured.

We can explore this subject in greater detail once I have a chance to dig deeper into some of the numbers.

Some initial findings: Ten quarterbacks from 2008 through 2011 were regular starters in both their first and second seasons. Five of the 10 posted significantly higher Total QBR scores in their second seasons. Three others posted second-year Total QBR scores that were very similar to their first-season scores. Two others, Bradford and Matt Ryan, posted significantly lower scores in their second seasons.

Ryan was the only one of the bunch with a stellar first-year Total QBR score. His was 74.1 in 2008, well above the 50-point average and among the top few scores in the league. We could say he "slumped" to a 56.6 in his second season, and that is surely what people will say happened if Wilson, Luck or Griffin III aren't as good in 2013 as they were during their sensational 2012 rookie seasons.

A smart bettor would take the "under" when projecting whether any player will improve or regress following a stellar season. The difference with players coming off rookie seasons is that we've seen less of them, making it tougher to set expectations. Nothing I saw from Wilson or Luck made me think either had significant holes in his game. Griffin is in a different category because he's coming off major knee surgery and he ran an offensive system that remains relatively untested in the NFL.