1983 Chicago Blitz season

Allen had been out of coaching since 1977; he had been a candidate for the vacant head coaching position with the Chicago Bears a year earlier; he'd made his mark in the NFL a quarter-century earlier as the Bears' de facto defensive coordinator. However, Bears owner George Halas had never forgiven Allen for defecting to the Los Angeles Rams in 1965. The feeling was mutual; Allen relished the chance to get the better of the rival Bears. Allen immediately became the "face" of the new team, and set about putting together the best 40-man roster he could find. The result was a team loaded with NFL veterans that was the early favorite to be the new league's first champion.

The Blitz finished in a tie for the Central Division title with the Michigan Panthers. However, the Panthers were awarded the division title after sweeping the Blitz in the regular season, and would go on to become the league's first champions. In the playoffs, the Blitz blew a 21-point lead over the Philadelphia Stars, losing 44–38 in overtime.

The Blitz was one of the strongest teams in the league. Indeed, some suggested that the Blitz and the two finalists, the Stars and Panthers, could have been competitive in the NFL. However, they struggled at the gate, averaging only 18,100 fans—a total that looked even smaller in the relatively spacious configuration of Soldier Field. These numbers were very similar to the gates for the Stars and Panthers in their first year. Both of those franchises would see dramatically higher attendance numbers in their second season based on their on-field success in their first year.

Diethrich lost millions of dollars in 1983. Although he, like most of the other owners, knew that he could expect years of losses until the USFL established itself, he soon tired of flying between his home in Phoenix (he was the founder of the Arizona Heart Institute) and Chicago. Indeed, he had actually sought a team in Phoenix when the USFL initially took shape, but backed out when he could not hammer out a stadium deal. Years later, he said that spending three days a week in Chicago or wherever the Blitz were playing made it difficult to continue his heart research, and led him to conclude he could not be an absentee owner in the long run.