Breaking news from Twitter, courtesy of Jon Heyman of CBS Sports:
K-rod is being called up by #brewers today. was opt-out day.— Jon Heyman (@JonHeymanCBS) May 15, 2013
There is no news on what the corresponding moves would be, and Adam McCalvy notes that the Brewers haven't made an announcement yet. The Brewers would need to clear a 25-man and 40-man roster spot to add him to the active roster. He had pitched well in the minors, putting up four scoreless innings between Brevard County and Nashville with seven strikeouts and three walks. The Brewers had to make a decision on him today, whether to add him to the roster or give him his release.
We will provide updates as we hear more details.
UPDATE: Ron Roenicke has confirmed that K-Rod is on his way to Pittsburgh. If he arrives in time, the roster move will be announced before the game.