Hopefully FM-106.7 will carry all the Nats matches - AM-980 (ESPN Radio in this area) has too many football commitments (NFL, Maryland, Virginia Tech etc) and too many of the matches will be seconded to low-power AM-570; also if the Orioles go through tonight anything else could get bumped down.
UPDATING: Rang the station just now and the person who answered said he wasn't sure but he thinks they will be carrying all the Nats matches.