Larry Tamburri, president of the PSO, told the Post-Gazette, "This was Andrew's decision. His life has gotten more complicated. His job at Lyric Opera [of Chicago, where he is music director] has grown. We understand his decision."

The orchestra hasn't yet formed a search committee to look for a replacement.

Following the departure of music director Mariss Jansons in 2004, the Pittsburgh Symphony, rather than selecting another music director right away, installed an artistic triumvirate: the three-conductor team includes Davis, principal guest conductor Yan Pascal Tortelier and Marek Janowski, holder of an endowed guest conductor chair.

Tamburri told the Post-Gazette, "We are not wedded to this model. It is a new model for an orchestra in America to be trying. We have found parts of it that have been interesting and enlightening and parts that don't work as well. We will either have to find ways to make it work within the model or work outside of it. We want to do what is best for the artistic future of the organization."

Whether the triumvirate model is continued will depend largely on who is hired and how that person feels most comfortable working, according to the paper.