Washington Nationals TV play-by-play announcer Bob Carpenter is saying, “See you later!” to the club after this season, his 20th in the role with the club’s local broadcaster, the Mid-Atlantic Sports Network. Carpenter announced his plans at the start of MASN’s telecast Monday from Nationals Park, where the team was scheduled to host the Baltimore Orioles in an exhibition finale. Washington is set to open the regular season Thursday against the visiting Philadelphia Phillies.