The Office of the Commissioner of Baseball announced the suspension on Friday.
Estevez, a right-handed pitcher, tested positive for metabolites of Stanozolol and Nandrolone. A member of the Dominican Summer League Cubs, his suspension will be effective at the start of this season.
Free agent Minor League left-handed pitcher Jorge Navarrete also received a 50-game suspension after refusing to take a drug test. The suspension of Navarrete is effective immediately upon his signing with a Major League organization.
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter@CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.