Oakland, CA-based metallers MACHINE HEAD have been in the process of searching for a temporary bassist replacement for this summer’s Mayhem Festival in the US.

As part of his new blog, entitled Just A Vessel, guitarist/vocalist Robb Flynn updates on the search:

"Today is the last day for tracking guitars on the demo as we're getting ready to begin try-outs tomorrow (Friday). Got eight guys lined up so far, some "known" guys, some dudes who are under the radar, all have touring / stage experience. It's exciting in some ways, and weird in others, I never thought I'd be going through this process again, and it fucks with my head from time to time.

It's just a fill-in slot for Mayhem, but these guys have to deliver on several levels, they got a bit of big shoe to fill, the dude who used to be onstage left was a presence, so we're going to test these guys out musically, performance-wise, creatively, and see if there's any kind of chemistry there. I'll let you know how it goes next week."

Read Flynn's complete update at this location.

Machine Head and bassist Adam Duce parted ways earlier this year. According to a brief band statement, "the split is amicable, and Machine Head would like to wish Adam the best with his current and future endeavours. The band will continue on for the time being as a three-piece and have begun the writing process for their follow-up to 2011's Unto The Locust. A late 2013 release is projected."

Both MASTODON and Machine Head are taking part in this summer's Rockstar Energy Drink Mayhem Festival, which runs June 29th to August 4th and is headlined by ROB ZOMBIE.

However, the two bands will team up for an off-date show July 25th in Cleveland, OH at The House Of Blues.

The complete Rockstar Energy Drink Mayhem Festival routing is as follows:

June

29 - San Bernardino, CA - San Manuel Amphitheater
30 - Mountain View, CA - Shoreline Amphitheatre

July

2 - Boise, ID - Idaho Center Amphitheatre
3 - Auburn, WA - White River Amphitheater
5 - Phoenix, AZ - Desert Sky Pavilion
6 - Albuquerque, NM - Isleta Amphitheatre
7 - Denver, CO - Fiddler’s Green Amphitheatre
10 - Toronto, ON - Molson Canadian Amphitheatre
12 - Burgettstown, PA - First Niagara Pavilion
13 - Scranton, PA - Toyota Pavilion at Montage Mountain
14 - Darien Center, NY - Darien Lake PAC
16 - Mansfield, MA - Comcast Center
17 - Bangor, ME - Bangor Waterfront
19 - Camden, NJ - Susquehanna Bank Center
20 - Saratoga Springs, NY - SPAC
21 - Hartford, CT - The Comcast Theatre
23 - Holmdel, NJ - PNC Bank Arts Center
24 - Bristow, VA - Jiffy Lube Live
26 - Noblesville, IN - Klipsch Music Center
27 - Tinley Park, IL - First Midwest Bank Amphitheatre
28 - Clarkston, MI - DTE Energy Music Theatre
30 - Atlanta, GA - Aaron’s Amphitheatre at Lakewood
31 - Tampa, FL - Live Nation Amphitheatre at the Florida State Fairgrounds

August

2 - Austin, TX - Austin360 Amphitheater
3 - The Woodlands, TX - Cynthia Woods Mitchell Pavilion
4 - Dallas, TX - Gexa Energy Pavilion