Weird but as @eddie83 mentioned, the two off days is just an odd consequence of the 2x2 structure of facing your assigned interleague rival. Looking at some other teams' schedules, the Mets have a similar situation later this year around two Yankees games, the Giants have a similar situation around two Athletics games, etc. Some teams have an oddity the O's don't which is a Sunday off-day after a Fri/Sat two game series with their regional rival.