Deryk Hooker won't be taking the mound tonight for the Quad-Cities River Bandits as scheduled.

Instead, the right-handed pitcher will be serving the second game of the 50-game suspension he received late Thursday from the commissioner's office after testing positive for a violation of baseball's Minor League Drug Prevention and Treatment Program.

Hooker, a seventh-round pick of the Cardinals in 2007, was cited for a "drug of abuse'' violation. Drugs and substances that fall under that classification include marijuana, cocaine, morphine, codeine, heroin, LSD, ecstasy, GHB and PCP.

The 19-year-old from San Diego was scheduled to be on the back end of the River Bandits' tandem rotation tonight at Wisconsin.

"It's a disappointing thing for him, and he'll have to learn from it,'' Quad-Cities manager Steve Dillard said. "There are consequences when you make poor decisions, and hopefully this wakes him up a bit.''

St. Louis general manager John Mozeliak expressed disappointment as well, telling the Associated Press, "How he deals with it will be a big test for him.''

By rule, Hooker cannot remain with the team or return to extended spring training while he is suspended.

"It will be a tough couple of months for him,'' Dillard said.

Andres Rosales will fill Hooker's roster spot and is expected to pitch Saturday. Miguel Tapia will move up one day into Hooker's slot in the tandem rotation tonight.

Hooker pitched in four late-season games for Quad-Cities a year ago, going 0-1 with a 1.61 ERA in four starts for the River Bandits after earning a promotion from short-season Johnson City.

In the minors, the 50-game suspension is mandatory for a first-time violation. A second-time offense leads to a 100-game suspension, and any player who fails a test three times receives a lifetime ban.

Hooker's suspension is the result of a drug test taken during spring training, a time when all players are tested. All minor league players also receive unannounced random tests throughout the season.

Mandatory drug testing has been a part of minor league baseball since 2001, although many organizations required testing at the minor league level prior to that date.

Penalties for violating the policy were upgraded in 2005, and Hooker is the second Quad-City player to be penalized by the commissioner's office since that time. In 2006, reserve outfielder Yonathan Sivira was suspended for 50 games after testing positive for using a performance-enhancing substance.