Braves minor league second baseman Mikey Reynolds has been suspended 50 games without pay for testing positive for a performance-enhancing substance (methylphenidate) in violation of the Minor League Drug Prevention and Treatment Program.

Methylphenidate is a stimulant, a prescription drug used to treat hyperactivity disorder. It has trade names such as Ritalin, and major league and minor league players must have a waiver in order to use it. Reynolds did not have a waiver.

“You’ve got to be aware of what’s allowable and what’s not,” said Bruce Manno, Braves assistant general manager and director of player development. “Everybody is informed and everybody knows exactly what is and what’s not permissible to take. It’s disappointing.”

Reynolds, 23, was batting .188 in 18 games at low Single-A Rome, with three extra-base hits (no homers), three RBIs, four stolen bases and a .268 on-base percentage. He is primarily a second baseman but has also played some shortstop.

The Pennsylvania native was a fifth-round pick by the Braves in the 2013 June draft out of Texas A&M, and hit .309 with nine extra-base hits (three triples, two homers), eight stolen bases and a .402 OBP in 44 games last year at short-season Danville in rookie ball.

“We spend an awful lot of time educating our guys (on the drug policy), and we do it over and over again,” Manno said. “So there should be no grey area in terms of knowing what’s permissible and what’s not. It was a mistake. Got to learn from it. I hope other players learn from it.

“That’s the big thing, too — I hope the guys, when this happens and you see this, it should send a message to everyone that, you know what, if I’m not sure I need to ask.”