In unfortunate news, bassist Craig Gruber died at the age of 63 today after a long fight with stage three prostate cancer. 

(Pictured here with Billy Sheehan) 

While he might not be a household name, hard rock aficionados know who Gruber is: a bass player with Elf and Rainbow, who also played with Ronnie James Dio, Gary Moore, The Rods and more.

Check out Gruber's work with Rainbow here: 

Gruber will be sorely missed.