Mastodon have been confirmed to support Metallica on a Mexico/South America run. Dates are as follows:
March 01 Guadalajara, Mexico @ Estadio Tres de Marzo
March 03 Monterrey, Mexico @ Estadio Universitario
March 05 Guatemala City, Guatemala @ Estadio Mateo Flores
March 07 San Jose, Costa Rica @ Saprissa Stadium
March 08 Panama City, Panama @ Plaza Figali
March 10 Bogota, Colombia @ Park Simon Bolivar
March 12 Caracas, Venezuela @ La Rinconada
March 14 San Juan, Puerto Rico @ Coliseo de Puerto Rico