Mastodon guitarist Bill Kelliher is currently in a London hospital, recovering from an undisclosed illness.
The guitarist was admitted on November 3 and was forced to miss European dates on the Unholy Alliance Chapter 3 tour with Slayer, Trivium and Amon Amarth.
He is said to be improving. The band are continuing as a trio until Kelliher makes a full recovery.
Mastodon will return to the UK to take part in All Tomorrow’s Parties in Somerset on December 7.