This isn't the first time college football players have started a boycott

The proposed player boycott by Gophers football players isn't the first time college football players have taken a stand.

Last year, a Missouri boycott led to the firing of the university president and an Oklahoma boycott was effective at closing a fraternity. In both cases, the boycotts had the support of coaches.

Here are some of boycotts over the past 50 years in college football:

• Missouri 2015: After a series of incidents on campus raised racial tensions at the Columbia, Mo., school, more than 30 University of Missouri football players announced on Nov. 7 that they would not practice or play any games until University President Tim Wolfe, whose response to the incidents was widely criticized as insufficient, was fired. The boycott, in concert with a student organization dubbed "Concerned Students 1950," became team-wide the next day and drew the support of coach Gary Pinkel and his staff, threatening the team's Nov. 14 game against Brigham Young. On Nov. 9, Wolfe resigned, and players returned to practice.

• Oklahoma 2015: With the support of coach Bob Stoops, Oklahoma football players walked out of a spring practice to protest a video that had become public of Sigma Alpha Epsilon fraternity members chanting racist insults. University President David Boren ordered the fraternity closed and severed the school's ties with the organization, and began expulsion proceedings against organizers of the chants.

• Minnesota State 2014: Players at the Mankato campus refused to take part in spring practice as a show of support for interim coach Aaron Keen, who had replaced coach Todd Hoffner in 2012 when Hoffner was arrested and eventually fired after photos of his naked children were found on his cellphone. A district court judge cleared Hoffner of child abuse charges and ordered him reinstated, but the players balked when Hoffner arrived to take charge again. A day after boycotting practice, Hoffner met with the players, who agreed to drop their objections and return to practice.

• Grambling 2013: Upset over the firing of coach Doug Williams and the inferior condition of their training facilities and playing conditions, players at the historically black college skipped two practices to call attention to their plight. When the school didn't immediately agree to upgrade their infrastructure and travel arrangements, only 22 players showed up to board buses for their Oct. 19 game at Jackson State. The game was declared a forfeit, and the school was forced to pay a penalty. Williams reached out to his former players a few days later, and after the school agreed to greater investments in the program, the team returned to finish the season.

• Syracuse 1970: Nine African-American players, angry at discriminatory policies of coach Ben Schwartzwalder and his all-white coaching staff — among other thing, white players received better medical care and educational support, the players asserted, and preference in starting assignments — boycotted spring practice and announced their intention to skip the season opener against Kansas. Schwartzwalder responded by dismissing the players, incorrectly dubbed the "Syracuse 8," white players staged a one-day walkout in support of the coach, and the game was played shortly after a violent confrontation between police and about 400 students.

• Indiana 1969: When 10 African-American players boycotted a November practice to call protest racist treatment and remarks from the coaching staff, coach John Pont told the "IU 10" that they would be kicked off the team if they didn't immediately return. The next day, they were dismissed, missing the final three games of the season, though Pont allowed the players to remain on scholarship.

• Wyoming 1968: On the eve of their October game with Brigham Young, 14 Wyoming players approached coach Lloyd Eaton while wearing black armbands, and informed him they planned to wear the armbands during the game to protest the refusal of the Mormon church, which owns BYU, to allow African Americans to hold the priesthood. Eaton immediately unleashed a tirade on the players and kicked them off the team. A late-night meeting of the university trustees upheld the dismissals and the game, won by Wyoming amid chants from the fans supporting Eaton, drew national attention.

• San Jose State 1968: Also intent upon protesting the Mormon church's all-white leadership, black players at San Jose State announced they would not take part in the team's game with BYU. Protests erupted around campus, and the game was eventually played before an almost empty stadium.