Twelve Iowa football players in hospital

Twelve Iowa football players are recovering after being taken to University of Iowa Hospitals and Clinics Monday evening with a kidney condition, the Cedar Rapids Gazette reported on its website Tuesday.

The Gazette said the Iowa players have rhabdomyolysis, which is a breakdown of muscle fibers that releases myoglobin into the bloodstream. This can affect the kidneys and can be caused by excessive exercise.

This corresponds with a posting on the Facebook page of Iowa linebacker Jim Poggi, who wrote he was hospitalized after his urine turned brown.

The school released a clarification Tuesday night saying the players admitted were all participating in NCAA allowable winter workouts and that the symptoms for which the players were being treated were likely related to those workouts.

The school released a statement earlier Tuesday saying the players had been hospitalized, but were recovering.

"The student-athletes were admitted throughout the course of Monday evening," a University of Iowa staff physician said in a statement. "All of the individuals are responding well to treatment as of Tuesday morning. All are in safe and stable condition."

The school would not confirm the identities of the players or their individual medical conditions, but the staff physician and a football team physician confirmed Tuesday the players were responding well to treatment.

"Coach Kirk Ferentz is out of town recruiting, but he is aware of the situation and is being kept abreast of the progress being made," Gary Barta, Iowa's director of athletics, said in the school-released statement. "Our No. 1 concern is the safety of our student-athletes, so we are pleased with the positive feedback. Our next step is to find out what happened so we can avoid this happening in the future."

The school says it's not clear when the players will be discharged. A school spokesman, Steve Roe, says privacy laws prevent further comment.

Iowa offensive lineman Julian Vandervelde, who recently graduated from the program and was a member of the team's leadership group, defended Iowa's workout practices in an interview with The Associated Press.

"They are nothing if not concerned for the health of the players," Vandervelde said. "That's always the first priority, health and development. I mean workouts are never used to punish. It's always about improvement, and workouts are always well within the capabilities of the athletes asked to perform them."

Tuesday's announcement that a dozen players had been hospitalized was just the latest bad news to hit the program that just wrapped a disappointing 8-5 season.

Senior wide receiver Derrell Johnson-Koulianos was suspended for the Hawkeyes' Insight Bowl win over Missouri after an arrest on drug charges. Johnson-Koulianos pleaded guilty to marijuana possession while other drug charges against him were dismissed.

Running back Adam Robinson was dismissed from the team after being arrested for possession of marijuana in his hometown of Des Moines while on suspension for violating team rules.

Information from ESPN.com's Adam Rittenberg and The Associated Press was used in this report.