PITTSBURGH -- Orioles second baseman Brian Roberts visited concussion specialist Dr. Michael Collins in Pittsburgh on Tuesday and was given the same prognosis that he received two weeks ago -- rest.

O's president of baseball operations Andy MacPhail said the team will continue to take a "wait and see" approach with Roberts, who has not seen game action since May 16 at Fenway Park, where he started getting headaches after sliding headfirst into first base. The latest news means Roberts will not be back before the All-Star break, and his timeline beyond that point continues to be cloudy.

"I had heard two to three weeks minimal," manager Buck Showalter said of Roberts' diagnosis, which was relayed to him by assistant athletic trainer Brian Ebel. "He was just giving me timeframes. As far as what [activity is] going on between now and then, it probably wouldn't be too much different from what he's been doing, I would think."

Roberts was not at PNC Park, where the Orioles are facing the Pirates in Interleague Play, as the team had hoped, and Showalter said the second baseman went back to the hotel to rest and will likely fly back to Sarasota, Fla., on Wednesday morning.

Roberts has been cleared to begin a plan consisting of light upper-body exercise that was developed by Collins, who will see Roberts again in two weeks. This is the second time in as many seasons that Roberts has been bothered with a long-term injury; he missed 59 games in 2010 with a herniated disk in his lower back. The 33-year-old infielder also battled back and neck injuries in Spring Training after another headfirst slide into first base.