Defense Secretary Jim Mattis scrapped a policy Monday that allowed some military academy athletes to turn pro right after graduation.

In a memo, Mattis said all graduates of the military academies and the Reserve Officer Training Corps will have to serve at least two years of active duty before being allowed to consider offers from the NFL, the NBA or other professional sports organizations.

"The military academies and ROTC exist to develop future officers who enhance the readiness and lethality of our military services," Mattis said.

"During their first two years following graduation, officers will serve as full-fledged military officers carrying out normal work and career expectations of an officer who has received the extraordinary benefits of an ROTC or military academy education at taxpayer expense," he said.

The action by Mattis reversed the Defense Department policy enacted in May 2016 that allowed promising military athletes to defer active duty to allow them to play pro sports.

The Mattis memo came four days after Air Force Academy athletes hoping to be drafted into the National Football League learned that the academy would not approve waivers that would allow them to join the Ready Reserve and sign with a football team.

Pentagon chief spokesperson Dana White said the change in policy would take effect for this graduation class. She also noted that the Defense Department "has a long history of officer athletes who served their nation before going to the pros, including Roger Staubach, Chad Hennings and David Robinson."

Roger Staubach, a Hall of Fame NFL quarterback with the Dallas Cowboys, was a graduate of the U.S. Naval Academy. Hennings, an Air Force Academy graduate and A-10 Thunderbolt pilot, was a defensive tackle on three teams that won the Super Bowl with the Cowboys. David "The Admiral" Robinson, a Naval Academy graduate, was a Hall of Fame center with the NBA's San Antonio Spurs.

In recent years, some military academy athletes have been allowed to enter the draft for the NFL before fulfilling their two-year commitments. Last year, star Navy quarterback Keenan Reynolds was allowed to be drafted by the Baltimore Ravens in the sixth round of the 2016 NFL draft.

-- Richard Sisk can be reached at Richard.Sisk@Military.com.