http://www.bloodyelbow.com/2013/12/7...on-fox-9-fight

RRiding an incredible 6-fight win streak, UFC Welterweight Matt Brown was expected to face off against former interim champion Carlos Condit at UFC on Fox 9. Rumors started going around Friday evening that Brown had suffered an injury in training and the bout was in jeopardy.

On Saturday, Bleacher Report reported that the injury rumors are true and Brown will not be fighting next week:

Sources close to the fight confirmed the news with Bleacher Report on Saturday morning. The possibility of Brown's withdrawal was first reported by Twitter user Front Row Brian on Friday, but our sources told us that Brown's decision to withdraw from the fight was not actually made until Saturday morning.
As of now, it's unknown whether or not a replacement will be made to keep Condit on the card. With such short notice, it will be hard to find a suitable opponent to step in.

UFC on Fox 9 is scheduled for Saturday in the Sleep Train Arena in Sacramento, CA.

UPDATE: Brown took to Twitter to confirm the injury and withdrawal from the fight:

Matthew Brown ✔ @IamTheImmortal
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Thanks for the support guys. I regret to inform all that I am out of the fight with Condit. I herniated 2 discs in my lower back this week.
2:31 PM - 7 Dec 2013