Are you ready for some football history? You might have heard the NFL started in 1920 and is commemorating its 100th season with a season-long celebration of "NFL 100."
The game has come a long way in 100 years. The most obvious change from 1920 to today is the size of players, but there also have been many changes in the schemes and roles of individual positions.
We will take a look at this evolution, position by position, era by era, and see how the game has progressed from the previous era. It’s sometimes hard to notice changes on a year-by-year basis, but when comparing 20-year spans, you'll notice things that otherwise would be unapparent.
Time will tell where the league goes 20 years from now, but this is how the NFL has evolved over its first 100 years.
Note: All heights and weights are taken from pro-football-reference.com.