The matchup, which UFC officials first announced in May, was pulled so that Broughton can deal with a few personal matters.
Today confirmed the change, though UFC executives weren't immediately available for comment, and it's currently unknown if the promotion will have time to secure a replacement opponent.
UFC on FOX 4 takes place Aug. 4 at Los Angeles' Staples Center. The heavyweight scrap was expected to take place on the FUEL TV-broadcast portion of the preliminary card, which follows one fight
streamed on Facebook and precedes the night's FOX-televised main card.
Mitrione, who joined the UFC after a semifinal-round finish on "TUF 10," won his first five pro fights and surged into title contention. However, the NFL vet then suffered a unanimous-decision loss to Cheick Kongo at UFC 137 in October, which marks his most recent performance.
His intended opponent, Broughton, was expected to be fighting for his UFC life. After joining the UFC and picking up his seventh win in eight fights with a submission victory over Vinicius Queiroz at UFC 120, the former Cage Rage champion has since suffered back-to-back losses to Travis Browne and Phil De Fries.
With the change to the card, the UFC on FOX 4 lineup now includes:
MAIN CARD (FOX)
- Mauricio "Shogun" Rua vs. Brandon Vera
- Ryan Bader vs. Lyoto Machida
- Travis Browne vs. Ben Rothwell
- Joe Lauzon vs. Jamie Varner
- Cole Miller vs. Nam Phan
- Phil Davis vs. Wagner Prado
- DaMarques Johnson vs. Mike Swick
- Josh Grispi vs. Rani Yahya
- Phil De Fries vs. Oli Thompson
- Manny Gamburyan vs. Michihiro Omigawa
- Ulysses Gomez vs. John Moraga*