Blitz: The League is an American football game series by Midway as an unlicensed extension of their NFL Blitz series. Released after the NFL signed an exclusive licensing deal with Electronic Arts, this series is the first in the NFL Blitz series to have a mature rating.
Since Midway Games no longer had an NFL license, Blitz: The League focuses on a fictional league consisting of 18 teams known simply as "The League", whose history is written as a tongue-in-cheek parallel of the NFL's. The game also brings back the hard-hitting and violent gameplay of earlier Blitz games in a ramped-up manner.
Source: Wikipedia, "Blitz: The League", available under the CC-BY-SA License.