Marlins manager Mike Redmond was in his office around 7:30 a.m. Tuesday when a familiar face walked through the door. “Red, I’m here reporting for duty,” said the man with more than six decades of professional baseball experience to his credit. “I’m just going to go out there and do what I do best.” Jack McKeon, a special adviser to the Marlins, then put on his No. 15 uniform and took the field for the first time this spring. McKeon remains the organization’s primary link to its last World Series, managing that championship team that will celebrate its 10th anniversary this season. McKeon has served in different capacities for the team since, including one more stint as manager. This season, two of McKeon’s favorite players from that 2003 title team are back in Marlins uniforms. McKeon has a deep affinity for Redmond, who played a key role on that club as the backup catcher, and left fielder Juan Pierre, who was McKeon’s center fielder and, many believe, the team’s heart and soul. “I asked him, ‘How are you?’ ” Pierre said. “He said, ‘I’m 82.’ I was like, ‘Yeah, you were 72 when we won.’ “It was a big deal because he was old then.” McKeon will be a key figure in Redmond’s first spring training as a big-league manager as somebody he can use as a sounding board. Redmond, though, will hope this ends better than it did for the last Marlins manager who called McKeon a mentor. Ozzie Guillen was McKeon’s third-base coach in 2003 before being hired to manage the Chicago White Sox. Guillen returned to the Marlins a year ago for one ill-fated season that ended with him being fired as the Marlins held another fire sale. Though McKeon calls Guillen “a good baseball man,” he once warned the unfiltered former manager about the dangers of being so outspoken. “Even when he was here in ’03, he’d run his mouth pretty good,” McKeon said. “I told him, I said, ‘Hey, son. You want to be a big-league manager? Here’s what you got to do: Be a little more low-key. Quit (talking).’ ’’