Wiz Khalifa had to bail on a concert on the eastern seaboard because of a bad foot injury -- specifically, he got jacked up while putting in serious work ... MMA style.
Sources connected to the Pittsburgh MC tell TMZ ... Wiz fractured his ankle Friday night during an MMA training session, which left him unable to perform during Saturday night's Hot 104.7's Hot Summer 2019 showcase in Westbrook, Maine.
He was one the headliners on the lineup -- performing alongside acts like A Boogie wit da Hoodie, Ally Brooke, YK Osiris, Big Freedia and others -- but because he couldn't make it .