Possible Clues:

• Musician's the first in orchestra breaking a string
• One pulling out the stops, roasting nuts
• It groans for church musician
• Roasting (anag.)
• Ballpark figure
• Musician who may make intro sag
• Worker in service whose contribution may be partly voluntary?
• Sorting out inclusion of a musician
• He pulls out all the stops when performing!
• Trio sang arrangement for musician