The Red Sox are not yet divulging who will replace David Ortiz when the season opens and the veteran designated hitter, as expected, will not be ready to go. Still, a few players, including right-handed hitting Jonny Gomes, left-handed hitting Mike Carp and switch-hitter Daniel Nava are among those expected to be in the three- or four-man rotation the Red Sox plan to use. Roster considerations for extra outfield and infield spots will also factor into who will be used at DH. Gomes, who hits lefties well, is a leading candidate to be in the DH spot on Opening Day, when the Yankees start lefty CC Sabathia. Carp, who like Gomes has the kind of pop in his bat the Red Sox are looking for, is a strong candidate to face certain right-handed pitchers. Two names not in the discussion are first baseman Mike Napoli and catcher Ryan Lavarnway. “Those conversations are starting, and it’s just talking about the combination of guys who might be in a bench slot to a more regular at-bat DH-wise,” Sox manager John Farrell said yesterday. “We’re by no means at a point of saying this is who our DH is going to be, or this is who else is going to be on the roster, but those conversations are happening more in earnest.” Farrell said he has seen Lavarnway have better at-bats when he catches rather than when he has been a DH, so with Jarrod Saltalamacchia and David Ross as the veteran catchers, Lavarnway appears to be bound for Triple-A Pawtucket to get more seasoning as a catcher. Napoli has been in good health and has made enough defensive improvement at first base that Farrell does not want to take the glove out of his hand.