The Office of the Commissioner of Baseball announced today that Tampa Bay Rays Minor League player Matthew Walker has received a 50-game suspension for testing positive for an amphetamine, a performance-enhancing substance, in violation of the Minor League Drug Prevention and Treatment Program.The suspension of Walker will be effective immediately. Walker is currently with Single-A Vero Beach of the Florida State League.Since mandatory drug testing was instituted, a total of 182 suspensions have been doled out across baseball for a total of 5,725 games. The following is a summary of drug violations, based upon The Biz of Baseball's detailed Drug Violations page (index.php?option=com_content task=view id=996 Itemid=85):20082 major leaguers* 2 - PEDs * Eliezer Alfonzo was part of the Giants 40-man roster, but at the time of the suspension was playing at Triple-A Fresno.* Cota was penalized under the major league drug program, even though he has not been on a major league roster since last June 15, when he was released by the Pittsburgh Pirates. The reason he was covered by the major league plan rather than the minor league program wasn't announced. 9 minor leaguers4 - PEDs1 - Amphetamines1 - Failure to Test1 - Human Growth Hormone1 - Stanozolol Metabolites 1 - Drug of Abuse 20078 major leaguers5 - PEDs3 - Stimulants (Neifi Perez twice)29 minor leaguers17 - PEDs2 - Failure to Test8 - Drug of Abuse2 - Unknown (not identifed by MLB in release)20063 major leaguers3 - PEDs24 minor leaguers21 PEDs3 - Drug of Abuse6 Venezuelan Summer League6 - PEDs200512 major leaguers12 - PEDs90 minor leaguers90 - PEDsSource: Major League Baseball. Business of Sports Network research Maury Brown is the Founder and President of the Business of Sports Network (http://www.businessofsportsnetwork.com/), which includes The Biz of Baseball (http://www.bizofbasketball.com/), The Biz of Football (http://www.bizoffootball.com/), The Biz of Basketball (http://www.bizofbasketball.com/) and The Biz of Hockey (http://bizofhockey.com/). He is contributor to Baseball Prospectus (http://baseballprospectus.com/news/?author=124), and is available as a freelance writer.Brown's full bio is here. (http://www.businessofsportsnetwork.com/index.php?option=com_content view=article id=47 Itemid=18) He looks forward to your comments via email and can be contacted through the Business of Sports Network (http://www.businessofsportsnetwork.com/index.php?option=com_contact view=contact id=2 Itemid=29).