Craig Kimbrel hasn’t been good overall for the Dodgers this year, but his struggles against lefties specifically might keep him off the playoff roster. Dodgers reliever Craig Kimbrel is on the postseason bubble after a season in which he has never been able to put together a prolonged hot stretch out of the bullpen. On Sunday afternoon, before Los Angeles took on Colorado in the third game of their season-ending six-game series, L.A. manager Dave Roberts met with the media for his usual pregame scrum in the home dugout at Dodger Stadium. Roberts was asked if, in a bullpen that…