It's just a rumor so far, but per Sports by Brooks, Mack Brown is likely to be forced out at the University of Texas. 

Multiple sources, including one inside UT football program, told me today Mack Brown will likely be forced out at Texas    

This rumor is right after a radio station in Kansas said that Brown was likely to retire after this season. Brown, though, denied that rumor, saying he plans to coach for a long time.

Brown's Longhorns have fallen out of the top 25 in the latest Coaches Poll after Texas' loss to Baylor on Saturday. Texas finished the regular season with a 7-5 record in 2011, but were once again under .500 in the Big 12, going 4-5 in the conference. Texas had their worst season in recent memory in 2010, going 5-7 and 2-6 in conference.

We'll see if something actually comes to this rumor, but "multiple sources" indicates that there may actually be something to this.