User blog comment:MightySeddieWarrior/Let Sam Sing!!! (Petition! Please Sign!)/@comment-1976613-20110715061638

Sockstar is right, Jennette signed with Capitol Records Nashville and not Sony Music/Columbia, who have a deal with Nickelodeon and since she doesn't have that on her contract/the network isn't getting paid by the label to have her sing on the show, therefore Jennette doesn't sing on the show.