In an unexpected development Anthony Pettis will now make his first UFC lightweight title defense against former Strikeforce fighter Josh Thomson at UFC On FOX 9.

The UFC had originally been looking to put Pettis up against TJ Grant, but Grant is still recovering from a concussion that kept him out of a title fight with Ben Henderson last month and won’t be fit in time so yet again a golden opportunity has passed him by.

“I am still not yet 100% and can’t commit to fight. UFC is going with someone else instead,” Grant said in a statement. “It sucks but it is the best for both myself and the UFC. Please don’t worry. I’ll be back and if I gotta fight someone else to get back to where I wanna be then that’s what I’m gonna do. I’m not bitter.”

Grant’s loss is Thomson’s gain as he now gets the opportunity instead.  A former Strikeforce champion, Thomson made a big impression on his return to the Octagon earlier in the year, becoming the first man to ever TKO former No.1 contender Nate Diaz.

Prior to that Thomson had lost out in via split decision fight in a rubber match with Gilbert Melendez for the Strikeforce 155lb title and his recent record is only 4-3 since 2009 so he’s a slightly unusual choice for a title shot.

However, he is currently No.5 on the UFC’s lightweight rankings, and with those above him (Ben Henderson, Gilbert Melendez, TJ Grant and Gray Maynard) all ruled out either due to having recently fought for the title or through injury he is next in line.

With five wins in a row including a win over Donald Cerrone last time out to his name, perhaps the No.6 ranked Rafael Dos Anjos would have been more deserving of the title shot, but Thomson has more of a name and is rarely ever in a boring fight so this should prove to be a highly entertaining encounter.

Pettis Vs Thomson will serve as the main event at ‘UFC On FOX 9’ on December 9th which already has a bantamweight bout between Urijah Faber and Michael McDonald set for the main card.