Leyba tested positive for the performance-enhancing substance Boldenone, an anabolic steroid.
"We were disappointed to learn of this news and hope that Domingo will take the time away from the game to reflect on his actions and learn from his mistakes," the Diamondbacks said in a statement.
The 24-year-old from the Dominican Republic hit .280 with five RBI in 21 games with the Diamondbacks last year and batted .300 with 19 homers and 77 RBI in 112 games at Reno of the Triple-A Pacific Coast League. He is considered one of Arizona's top prospects and was 4 for 16 with a home run during spring training this year.
Leyba signed with Detroit in 2012 and was traded to Arizona with left-hander Robbie Ray in December 2014 as part of the three-team trade that sent shortstop Didi Gregorius from the Diamondbacks to the New York Yankees.
He became the fifth player suspended this year under the major league program, three shy of last year's total. Houston pitcher Francis Martes, Pittsburgh outfielder/infielder Pablo Reyes, Colorado pitcher Justin Lawrence and free agent pitcher Victor Alcantara previously were banned for 80 games each.
Three players also have been suspended this year under the minor league drug program.