There’s a new sheriff in town for the New York Mets, and it’s a guy who has been in sticky situations before — Sandy Alderson, the former A’s, Padres and Major League Baseball executive. Alderson served four years as a Corps officer, including a tour of Vietnam. The Associated Press reported Thursday that Alderson would be introduced the Mets’ general manager as soon as Friday. Speculation has centered on Alderson for the past few days. Alderson was GM in Oakland from 1983-97. His team won three American League pennants and captured the World Series in 1989. He faces a challenge…