There has been rumors, some of which started months ago, regarding Dwayne Johnson and a possible return to the ring at WrestleMania 25. Unfortunately, this is probably the most unlikely scenario of any that we've seen, including Hogan, Austin, and Mickie Rourke. The Rock has stated numerous times in recent interviews that he is done with professional wrestling and focusing solely on his acting career.
Most recently, the Rock told the AP Press that he has no intentions of returing to the ring. "I retired five years ago. That was a character I loved playing. That gave me the opportunity to move on and to transition. That created a platform for me that can never be duplicated."
WrestlingObserver.com reports that at one point, Vince McMahon had thought about another Rock/Austin match simply due to the fact that he wanted a major main event for the 25th anniversary. However, Johnson's advisors definitely wouldn't want him doing it and he hasn't talked about doing another match in years.
Prior to 2005ish, the Rock had discussed working with someone like Rey Mysterio, Sting (impossible due to TNA contract), or Randy Savage (impossible due to obvious reasons). Johnson thought these guys would be great from a historical standpoint and he had always wanted to work with them. It's been three or four years, however, since the Rock has discussed working a match and it definitely seems as if his wrestling career is over.