As I'm sure others have noticed, King Barrett hasn't been seen with other members of the League of Nations in their various adventures to thwart the ambitions of Roman Reigns. He appeared on the TLC kickoff show, but was nowhere to be seen at TLC itself or Raw last night.
According to Dave Meltzer, Barrett has suffered some sort of injury that remains undisclosed at the time. Meltzer believes that the injury, whatever it is, took place sometime prior to TLC and is why Barrett hasn't been used in any of the various physical altercations. It's noted that Barrett did wrestle last at the Tribute to the Troops taping, so it's possible the injury occurred there or, possibly, before then and was exacerbated by the action of TTTT. Again, exactly what the injury is and how severe it is wasn't mentioned in the report.
I've been a fan of Barrett since his NXT days, but he's just not reliable because he seems to be pretty injury prone. He's missed significant time due to elbow or shoulder problems in the past and these injuries always seem to come about when he has some momentum built up or is in the process of building it up. Maybe Barrett should consider hanging up his boots because this unreliability, although nobody's fault, is unreliability all the same that's going to prevent him from rising higher than he is. I think he'd be a great commentator, he's comfortable on the mic and can be quite entertaining when he's left to his own devices.