On the night of March 28–29, 1984, Robert Irsay, then-owner of the Baltimore Colts of the National Football League (NFL) covertly moved the team to Indianapolis, Indiana, where it would begin play as the Indianapolis Colts in the 1984 NFL season.

The city government of Baltimore, Maryland, had proved unwilling to replace the team's three-decade-old home stadium, and the Maryland General Assembly was on the verge of passing legislation allowing the city to seize the team via eminent domain. The move embittered many Baltimoreans for decades. Its effects on the NFL include a similar controversy that 12 years later brought Baltimore its current franchise, the Ravens.

The Colts had played at Baltimore Memorial Stadium since the 1953 NFL season, sharing the facility with Major League Baseball's Baltimore Orioles. In May 1969, the city of Baltimore announced it would seek a substantial increase in Memorial Stadium rental fees from Colts owner Carroll Rosenbloom and the team itself. Rosenbloom had already called the stadium "antiquated" and had threatened to stop playing there unless improvements were made. Rosenbloom even considered using $12 million to $20 million of his own money to help fund the building of a new football-only stadium on land in adjoining Baltimore County. In November 1971, Rosenbloom announced that the Colts would not return to Memorial Stadium when their lease ran out after the 1972 season and that he was no longer interested in negotiating with the city. He wanted out of Baltimore for several reasons: team revenue, disputes with Baltimore Orioles owners over stadium revenue, a running feud with the Baltimore press, and his new wife's desire to move to the West Coast. After the 1971 season, Rosenbloom and Irsay swapped teams, the former taking ownership of the Los Angeles Rams and the latter the Colts.

In 1971, Baltimore mayor William Donald Schaefer and Maryland governor Marvin Mandel created a committee to examine the city's stadium needs. Their report was a blow to Memorial Stadium. Some of the problems mentioned: 10,000 of the stadium's seats had poor views of the field; 20,000 seats were outdated bench seats without back support; 7,000 seats were poorly constructed temporary bleachers that were installed for football games only. There was not enough office space for the front offices of either the Orioles or Colts, much less both teams combined. The teams had to share locker rooms. The upper deck of Memorial Stadium did not circle the field, ending instead at the 50-yard line. Any expansion plans for the stadium had usually mentioned less attractive (and less expensive) end-zone seats, not upper-deck seating. Even the bathroom facilities were deemed inadequate.

Maryland's planners proposed the Baltodome, a facility near the city's Inner Harbor known as Camden Yards. The new stadium would host 70,000 fans for football games, 55,000 for baseball, and 20,000 as an arena for hockey or basketball. For an estimated $78 million, the city would build a facility that would have kept all parties happy: Baltimore Mayor Schaefer, Governor Mandel, Orioles owner Jerold Hoffberger , Colts owner Irsay, and the Stadium Complex Authoritym, whose chairman, Edmond Rovner, said in 1972, "A major consideration in Mr. Irsay's trading of franchises was the city's firm commitment to proceed with these plans".

However, the proposal did not receive support to pass the Maryland legislature, in spite of assurances that contributions from taxpayers would be limited strictly to city and state loans. On February 27, 1974, Mandel pulled the plug on the idea. Hoffberger was blunt: "I will bow to the will of the people. They have told us what they want to tell us. First, they don't want a new park and second, they don't want a club." Irsay was willing to wait. "It's not a matter of saying that there will be no stadium. It's a matter of getting the facts together so everybody is happy when they build the stadium. I'm a patient man. I think the people of Baltimore are going to see those new stadiums in New Orleans and Seattle opening in a year or two around the country, and they are going to realize they need a stadium...for conventions and other things besides football."

Hyman Pressman, Baltimore's comptroller, was against using any public funds to build a new stadium. During the 1974 elections, Pressman had an amendment to the city's charter placed on the fall ballot. Known as Question P, the amendment called for declaring "the 33rd Street stadium as a memorial to war veterans and prohibiting use of city funds for construction of any other stadium." The measure passed 56 percent to 44 percent, and the same political motivations that had been used to upgrade Baltimore Stadium, originally built in 1922, in the late 1940s and rename it Memorial Stadium, effectively destroyed any chance of a new, modern sports complex being built in Baltimore.

Although the Colts made the playoffs for three straight years from 1975 to 1977, there had still been no progress made on a new park for the team. Robert Irsay first spoke with Phoenix, Arizona, in 1976 and then Indianapolis, Indiana, in 1977 about the possibility of moving his team to one of those cities. In 1976, he acknowledged publicly that he had received an attractive offer to move the franchise to Phoenix. Then, in 1977, he said, "I like Baltimore and want to stay there, but when are we going to find out something about our stadium? I'm getting offers from towns like Indianapolis to build me a new stadium and give me other inducements to move there. I don't want to but I'd like to see some action in Baltimore." In 1979, Hoffberger sold the Orioles to Washington, D.C. attorney Edward Bennett Williams, who declared 1980 to be a trial year for the fans of Baltimore. He then went on to explain his concerns with Memorial Stadium, saying it had "inadequate parking and inadequate access and egress. Frankly, I don't know if those problems will ever be solvable at that location."