Marty Harrell ?

Who is this guy ? When Elvis is introduction the orchestra at some shows in 77`, he says "Our conductor Marty Harrell", and "Joe Guercio show Orchestra", why was not Joe Guercio the conductor?
Anybody have some pictures of this Marty Harrell on stage ?

Marty was the bass trombonist in the Joe Guercio orchestra, and sometimes filled in for Joe if he was sick or otherwise occupied.

Okei, thank you so much! (y)