The pitcher became the second player in a week to be hit with a lengthy ban by baseball chiefs after failing a test for a performance-enhancing substance.
MLB: 50-game ban for Oakland star Bartolo Colon after positive drug test
NEW YORK, USA // Bartolo Colon, pitcher with the Oakland Athletics, has been suspended for 50 games by Major League Baseball - just days after Melky Cabrera was hit with a similar ban.
The 39-year-old Dominican faces an immediate ban without pay after failing a test for performance-enhancing substances.
He will miss the rest of the normal season, and either the first ten games of next season or the playoffs if the A's reach them.
"I apologise to the fans, to my teammates and to the Oakland A's," Colon said in a statement.
"I accept responsibility for my actions and I will serve my suspension as required by the Joint Drug Program."
The A's pitcher, who was found to have abnormally high levels of testosterone in his system, has a 10-9 record in 24 starts for the American League club this season with a 3.43 earned-run average.
He struck out 91 batters and walked 23 in 152 1/3 innings with 161 hits surrendered, including 17 home runs.
Colon, who was to have started on Thursday, led Oakland in wins and innings pitched this season and had helped the A's move within one game of Tampa Bay and Baltimore for a wild-card playoff berth in the American League.
"The Oakland Athletics are disappointed to learn of today's suspension of pitcher Bartolo Colon," the team said in a statement.
"The organisation fully supports Major League Baseball's Joint Drug Prevention and Treatment Program and its efforts to eliminate performance-enhancing substances from our game."
Colon, who was working on a $2 million contract this season, has a 171-122 career record with a 4.05 career earned-run average with Cleveland, the Chicago White Sox, Los Angeles Angels, Boston, the New York Yankees and Oakland.
The ban comes a week after a 50-game ban was imposed upon San Francisco Giants star Cabrera, also a Dominican, for a positive doping test for testosterone.
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