Found it on Wikipedia... it was a back injury.
"2010
Roberts missed much of training camp with a herniated disc in his lower back. He recovered in time for Opening Day, but started the season 2–14 before suffering an abdominal strain stealing second base and being forced onto the 15-day disabled list, effective as of April 10. On July 12, Roberts began to play in rehab games without having a setback, as it is the first time he has been on the field since April 10. On July 23, Roberts returned to the Orioles' lead off spot for the first time since April 9.
2011
Roberts was injured on May 16 at Fenway Park when he slid into first base headfirst and hit the back of his head. He did not return for the remainder of the season.
2012
Due to Roberts' injury, he has not played any games as of May 2012. However, he travels with the team, and is an active member of the Orioles' dugout.
Steroid allegations
On September 30, 2006, the Los Angeles Times reported that during a June 6, 2006, federal raid, former relief pitcher Jason Grimsley named Roberts as a user of anabolic steroids. The Times reported that Roberts was one of five names blacked out in an affidavit filed in federal court.[4] However, on October 3, 2006, The Washington Post reported that San Francisco United States attorney Kevin Ryan said that the Los Angeles Times report contained "significant inaccuracies."[5] On December 20, 2007, the actual names in the Grimsley search warrant affidavit were revealed to the public. Roberts, Jay Gibbons, Andy Petitte and Roger Clemens were not actually named in the report and Miguel Tejada was named only for having a conversation about amphetamines.[6] Roberts, along with the other four players named, denounced the story.[5] Roberts was subsequently named in George Mitchell's report on performance enhancing drugs. According to page 158 of the Mitchell Report, Roberts lived with then-teammate Larry Bigbie in David Segui's house near the end of the 2001 season. Bigbie and Segui were regular steroid users; while they were using the performance enhancing drugs and Roberts was present, he asserted that he did not participate. According to Bigbie's testimony, Roberts told him in 2004 that he had injected himself with steroids "once or twice" in 2003.[7]
On December 17, 2007, Roberts released a statement in which he admits to using steroids on a single occasion.
“In 2003, when I took one shot of steroids,” he said. “I immediately realized that this was not what I stood for or anything that I wanted to continue doing. I never used steroids, human growth hormone or any other performance-enhancing drugs prior to or since that single incident. “I can honestly say before God, myself, my family and all of my fans, that steroids or any performance-enhancing drugs have never had any effect on what I have worked so hard to accomplish in the game of baseball.”
Roberts further stated that he had no ill-will against former Oriole Larry Bigbie whose testimony to the Mitchell Committee was responsible for his inclusion in the report.[8]"
