Perhaps years from now, if his potential turns into production, it will be this anecdotal offering that helps outline the reasons for his success. It’s not an uncommon story in baseball, a sport in which failure is found far easier than success on a daily basis. A touted prospect struggles to live up to lofty expectations and is demoted to fix what is broken, remembers what made him successful, restores his confidence and resumes his progression back to the big leagues where he remains for the rest of his career. For Justus Sheffield, the ending to his tale has yet to be written. He’s experienced only the struggles and the setback. But the Mariners hope, and he said he believes, that the rest will begin to fall into place this season.