Carlos Santana fits the mold of “difference-maker” the Mets desire, and team officials are willing to at least explore the possibility of adding the switch-hitting slugger to a lineup that could use another proven bat. An industry source confirmed Tuesday that the Mets have expressed interest in the free-agent first baseman, who is familiar to new manager Mickey Callaway from their time together with the Indians. FanRag Sports first reported the Mets’ interest in the 31-year-old Santana, who posted a .259/.363/.455 slash line with 23 homers and 79 RBIs last season. The Mets’ interest in Santana also underscores how underwhelmed team brass was with rookie Dominic Smith in the final six weeks of last season at first base. If Santana were signed, Smith would either be dealt to another club or sent to Triple-A, where the Mets would look to build up his potential trade value. But Santana could command a four-year contract, and the Mets will have competition for his services. And so, club officials are keeping an open mind as they search for pieces to complement Asdrubal Cabrera and Amed Rosario in the infield. The Mets do not seem inclined to pursue free-agent first baseman Eric Hosmer, who is represented by Scott Boras and could receive a contract worth upwards of $100 million. Another Boras client, third baseman Mike Moustakas, falls into the same category. At the general manager’s meetings, Mets assistant GM John Ricco indicated Smith and Wilmer Flores could still form a first-base platoon, with the club considering trade options that would bolster second base. Top possibilities include Jason Kipnis and Dee Gordon, both of whom are available.