LOS ANGELES — A baseball team’s postseason roster is often a work in progress. Yes, the Dodgers are getting the hang of this best-of-three first round, the playoff equivalent of clearing your throat. We knew as early as Sunday that Clayton Kershaw would not be on the Wild Card Series roster, after pitching into the sixth inning in the regular-season finale in Seattle. (And keep in mind that the list can and likely will change for each series should the Dodgers advance.) There were three catchers on the roster: Smith, Ben Rortvedt (the starter Tuesday night) and Dalton Rushing.