Jeff Zrebiec covered some of the roster possibilities over at Orioles Insider, but if the Orioles put Brian Roberts on the disabled list tomorrow and decide they want to bring up a reliever instead of another infielder, they must get special permission from the Commissioner's Office.
Since we're in the early days of the season, the players who were optioned out at the end of spring training -- who, logically, would be the first players called back -- must stay in the minors for 10 days. Players can be brought back earlier in case of an injury, but only when they replace a player at the same general position. So, if the Orioles want to bring up Justin Turner for Brian, they can do that, but if they want to bring up Kam Mickolio to bolster the bullpen while Mike Gonzalez works out his mechanical problems, they need clearance from above.
Club officials say it's still pretty much a formality.