What happened to Shayna Rose "Marina" on Fresh Beat band on the 6/24/11 episode?

I tried to google it but nothing came up. But I just saw the commercial and there was a new girl in her place. I hope that she's just sick and they didn't replace her, she's my daughters favorite character. Here is a link to the video http://www.nickjr.com/kids-videos/fresh-beat-giant-pizza.html