Jake Shields vs Ben Henderson headlines Chael Sonnen's 'Submission Underground' card on July 17

The Mean Streets of Oregon just got a whole lot meaner.

Former UFC middleweight title contender Chael Sonnen, who continues to stay afloat in combat sports with regional endeavors like this one, will try his hand at fight promotion with "Submission Underground," a grappling event that debuts this summer in Portland.

Inside a cage, "to ensure the safety of the competitors involved by preventing them from tumbling from a raised platform or mat," according to the release.

The main event pits World Series of Fighting (WSOF) standout Jake Shields opposite Bellator MMA attraction Ben Henderson. Aside from from their accomplishments on the grappling circuit, both welterweights shared the UFC Octagon in recent years.

FloCombat explains the modified Eddie Bravo Invitational Rules:

For eight minutes, a competitor can win only by scoring a submission. If there are no submissions, the match moves to an overtime period. The winner of a coin flip can elect to start the overtime period attacking from the back or from the "spiderweb" (arm bar) position. If one competitor scores a submission and his opponent does not, he is declared the winner. But if both competitors escape from submission attempts, the match moves to the next overtime round. After three overtime rounds, the competitor who escaped the quickest is declared the winner.

Here is the Submission Underground main card:

Jake Shields vs. Benson Henderson
King Mo Lawal vs. Vinny Magalhaes
Kenny Florian vs. Filipe Braga Costa
Ricco Rodriguez vs. Fabiano Scherner
Jens Pulver vs. Nathan Orchard

The event airs on FloCombat.com on Sun., July 17, 2016.