WWE has a new article online here on dot com that states their "sources indicate" that CM Punk is medically cleared for in-ring competition. This of course means he'll be able to defend the WWE Championship against Ryback in a TLC match on next week's WWE Raw.
They tout an official announcement will be made on Wednesday night's episode of WWE Main Event.
To take as much kayfabe out of this as possible, Punk underwent arthroscopic knee surgery in early December. He wanted to work Ryback at TLC but Vince McMahon wouldn't let him and told him as much in a meeting shortly after he had the surgery. Vince basically told Punk they had invested too much in him defending the title against The Rock at Royal Rumble and they didn't want to do anything to jeopardize that match.
The status of next Monday's WWE Championship match is unknown although there were preliminary plans of doing an angle to prevent the match from happening. As was seen on this week's Raw, another avenue was opened with McMahon stating if Punk "couldn't go" that Paul Heyman would face Ryback. This was practiced/rehearsed last week at a WWE Raw live event in New York City where Heyman actually took a bump through a table.