(NEXSTAR) – The ongoing Major League Baseball lockout means the opening day has been canceled or delayed for only the fifth time in the sport’s history. Spoiler alert – labor disputes are the key reason others have been affected, too.

After the MLB and the Players Association failed to reach an agreement by management’s Tuesday deadline, Commissioner Rob Manfred announced the first two series of the 2022 season, scheduled to begin on March 31, are off the schedule. This is the first time in 27 years that games have been canceled over a labor dispute.

Disputes postponed opening day on three prior occasions: 1995, 1990, and 1972. The strike of 1994-95 is the longest in MLB history, lasting over 230 days.

It caused not only the 1995 season to be delayed but ended the previous season early when a player strike began in August 1994. Games didn’t start again until late April that season after an agreement was reached.

Stephen Kazi, left, and Christopher Clark of the Los Angeles-based Fans on Strike organization picket outside Dodger Stadium in Los Angeles as fans drive up to the turnstiles to attend the Dodgers home opener against the Atlanta Braves on April 28, 1995. About 40 members of the organization handed out bumper stickers to incoming Dodger fans as well as toilet paper, which they instructed fans to throw onto the field during the game. (AP Photo/Chris Pizzello)

Five years earlier, in 1990, opening day was pushed back for a week amid yet another lockout. Players and owners were battling over free agency, arbitration, and revenue sharing, according to NBC Sports. The start of the regular season that year was pushed back, CBS Sports reports, but no games were formally canceled.

Baseball Commissioner Fay Vincent announces the settlement of the 32-day lockout after players and owners agreed to a four-year contract in New York, on March 19, 1990. At right is Milwaukee Brewers’ President Bud Selig. (AP Photo/Frankie Ziths)

MLB’s first-ever player strike canceled 1972’s opening day. Players were holding out for pension improvements, according to the MLB. Originally scheduled for early April, opening day was pushed back two weeks until owners and players reached an agreement.

This April 13, 1972 file photo shows Marvin Miller, executive director of the Major League Baseball Players Association, announcing an end to the baseball strike at a news conference in New York. Players shown are, from left, Gary Peters of the Boston Red Sox, Wes Parker of the Los Angeles Dodgers, and Joe Torre of the St. Louis Cardinals. At right is Dick Moss, general counsel for the association. (AP Photo/File)

Other regular-season games have been canceled before over disputes. In 1981, for example, a 50-day midseason strike over free agency compensation rules canceled 713 games.

Before these games, opening day was canceled only one other time – 1919. The season was delayed for a couple of weeks while teams waited for players to return from military service following the end of World War I. The last time the opening day was rescheduled was in 2020 when the COVID-19 pandemic pushed opening day into July.

As of Tuesday, only the first two series of the 2022 season have been canceled.

The Associated Press contributed to this report.