It has been clear for weeks that Johan Santana is unlikely to be ready for the beginning of the season, but team insiders say that the Mets are not in the market for starting pitching. Ever since the Mets slowed Santana’s throwing program last month, their private expectations for his April 1 availability have been even grimmer than their public line of “We’ll see.” In reality, there is very little chance that Santana avoids the disabled list at the beginning of the season, leaving the Mets in need of at least one additional starting pitcher — especially with Shaun Marcum still waiting to make his second spring start against big leaguers. Despite that, team sources say it is almost certain that Jeremy Hefner, and not one of the options available outside the organization, will begin the year in the rotation. Other internal choices include Colin McHugh and Jenrry Mejia, but Hefner seems to have the edge, particularly with Mejia headed back to New York for a follow-up on his physical exam. There are many available starters on the market, namely from the Dodgers’ starter surplus that includes Aaron Harang, ex-Met Chris Capuano and Ted Lilly. The Tigers are willing to move Rick Porcello, and Chien-Ming Wang drew attention last week by pitching six shutout innings for Chinese Taipei in the World Baseball Classic. Former Met Chris Young is in camp with Washington, but will not make that rotation unless a teammate is injured. He has a late March opt-out, and the Mets were interested until the end of the offseason, but are not so into the idea at the moment. “More likely we’ll go with what we have in here,” one Mets official said. A second source offered an even stronger statement: “We are not even in that (starting pitching) market right now.”