ST. PETERSBURG — Stefan Sanderling expects to feel a little nervous tonight. "I've always been nervous on the night before a first rehearsal, but this time it is a very unusual situation for me," Sanderling said early this month. "It will be strange."On Wednesday morning, Sanderling will be in front of the Florida Orchestra's musicians for the first time since the orchestra announced, last July, that he was stepping down as music director two years sooner than planned. At Mahaffey Theater, he will convene the first rehearsal for his only concerts with the orchestra this season, with Mahler's epic symphonic song cycle Das Lied von der Erde as the centerpiece of the program.Though he is billed as conductor emeritus and artistic adviser, Sanderling, 48, appointed music director in 2002, has had scant involvement with the orchestra this season until now. He is appearing essentially as a guest conductor."I'm in a situation which is very rare," he said. "As a music director, your task is not to make the next concert the greatest concert on earth. That's not why you're a music director. You have to accept that sometimes you have to have bad concerts, but in the long term you develop something with an orchestra. You have to take risks. You have to push people to the limit. You have to get on people's nerves. But as a guest conductor, all you have to do is shine for the week. You tell everybody how fantastic they are. You don't have to deal with the dark side."My situation now is I'm not the one and not the other. Whatever choice I make is inappropriate."Sanderling's unorthodox — and mostly unexplained — departure could lead to some awkwardness. But concertmaster Jeffrey Multer thinks most musicians will be glad to see him."Stefan made a decision that was best for him," Multer said. "I don't think anyone can say he shouldn't have done what he wanted to do. The Mahler is a great piece, and it's right in his wheelhouse. I think the orchestra will really want to step it up for him."In many ways, the orchestra has moved on post-Sanderling without missing a beat. A well-orchestrated search process for his successor is under way, with a series of guest conductors who are potential candidates as music director leading masterworks programs throughout this season, with more to come in 2013-14.Sanderling has kept a residence in St. Petersburg. His wife, Isabelle Besancon, is a cellist with the Sarasota Orchestra. German pianist Peter Rosel stayed at their house when he was a soloist with the Florida Orchestra this month. The ex-music director has not attended any of his old orchestra's concerts this season, though he did make it to a Sarasota Orchestra performance led by Thomas Wilkins, the Florida Orchestra's former resident conductor."You can imagine this has not been an easy situation for me," Sanderling said. "For 10 years, you were Mr. Music, and then you're not. There was no transition. It was like the pope. You are either the pope or you are not. My papacy is over."Sanderling, who was paid $256,486 a year by the Florida Orchestra, according to the nonprofit's most recent tax return available for public view, remains as music director of the Toledo Symphony Orchestra in Ohio, where he had a half-dozen classical programs on his schedule this season plus some additional events, such as the Mozart opera Don Giovanni. He mentioned a Beethoven Ninth that he conducted in Gera, Germany, but his late withdrawal from the Florida Orchestra engagements left his calendar unusually open, because most orchestras plan their seasons far in advance."All of a sudden, I have lots of time," said Sanderling, who in the past kept up a busy round of guest-conducting in between engagements in Florida and Ohio. He is scheduled to lead one more masterworks program with the Florida Orchestra next season.Does he want to be music director with another orchestra?"I've always been a music director," Sanderling said. "You only own what you have created over time. I hope that when someone adds things up that something positive came out of my contributions here. It's too soon to say. Yes, I would like to be music director again."But he acknowledged that his abrupt departure could raise questions from orchestras looking to hire a music director."I hope not but I cannot rule it out," he said. "Sometimes I wish not to think about it. Anyway I can't change it. I am the person I am with beliefs and convictions. You cannot change your beliefs or convictions depending on other people. You are what you are. I'm not willing to change that."In an interview, over his morning coffee and pastry, Sanderling declined to give specifics on his early exit. However, he previously had made it clear there were hard feelings between him and chief executive Michael Pastreich, who has been aggressive in trying to break the perennial cycle of costs exceeding income at the orchestra. He and the board made financial decisions that undoubtedly went against the music director's vision for the orchestra, such as cutting musicians' pay, though some of those losses were regained in a new contract last year.Pastreich planned to be on vacation this week, but he denied that had anything to do with Sanderling's presence on the podium."I'm coming back from my vacation early for the Sunday performance," Pastreich said. "I can't believe anything but that this will be the most riveting concert we'll do all year. I think it's a chance for Stefan to come back and make a statement. I think the concert will be a stunner."John Fleming can be reached at [email protected] or (727) 893-8716.