Before the Mariners game tonight Mike McCready of Pearl Jam played the national anthem. I tried to capture it on my cell phone but I guess the video is just not that great and you will have to trust me that he was there. On his jersey it had his last name and the number 59 which I think is a reference to the fact that the guitar he plays is a 59 strat.
You might be able to see the small set of amps behind home plate in these photos. They are kind of dark and people are standing in front of them.