Rienzo, a 23-year-old native of Sao Paolo, Brazil, came to the team as a free agent in 2006. He was 3-0 with a 1.08 ERA for Class A Winston-Salem as part of its 2012 starting rotation.
After the suspension was announced, for Rienzo testing positive for metabolites of Stanozolol, a performance-enhancing substance, the White Sox released a statement from Rienzo.
"I have been informed by Major League Baseball that I have tested positive for a prohibited substance, and as a result, I will be suspended for 50 games," Rienzo said in the statement. "I want to make it clear to Major League Baseball and the Chicago White Sox that I have never intentionally taken a prohibited substance.
"Unfortunately, during the offseason, I used a dietary supplement that I purchased at a health food store in my home country of Brazil, believing it to be legitimate. It is now apparent that the supplement was tainted. I understand that I am responsible for what I put in my body, and therefore have accepted the 50-game suspension. I look forward to returning to the game I love, and I appreciate the support the Chicago White Sox have given me during this process."
According to White Sox director of player development Buddy Bell, the organization found out about the suspension two weeks ago. At that time, Rienzo and his camp, which included his representative, Paul Kiner, decided to appeal through the proper channels.
They changed their mind after 10 days upon reviewing the history of getting suspensions overturned and knowing the process would take its toll on Rienzo if he continued to pitch through it. Taking the suspension immediately will bring back Rienzo around June 13 or 14, at which point he'll go back into the Dash rotation with a couple months of the season remaining.
"He was devastated at the positive," said Bell of Rienzo. "He's a great kid. You feel awful for this kid. They just have to pay attention. He just made a mistake, and we'll move forward. And we'll support him in whatever he needs at this particular time.
"We try to educate kids on these things. I don't know what's in GNC. I don't know what's available and what's not. I know what's prohibited, and kids have to pay more attention. Not sure if that's different in the foreign countries. I don't know, but they do have the information."
Bell believes Rienzo will learn from this experience, as will his teammates.
"Unfortunately, these kids learn in different ways," Bell said. "Knowing Andre the way I do, he will be a better person for it. He's a great kid anyway. Things like this have a way of helping you grow up.
"In terms of him professionally, we'll put someone else in his place and try to keep him as physically fit as we possibly can. When June 13 or June 14 comes around, he'll be ready to go.
"And we will continue to talk to him about what has happened. We are not going to brush it under the rug like it never happened."