While Batista may have been expected to make a one-time return for Wrestlemania 27 a few months ago, the feeling now is that he won't be coming in since there has been no contact between him and WWE, as far as anyone knows. It's believed he will sign with Strikeforce once he finished filming Scorpion King 3.
Another name that falls into the same category as Batista is Chris Jericho. It was expected by some that he would be back in time for Wrestlemania but that feeling has change. Most believe that Jericho won't be back anytime soon and won't be back for Wrestlemania, but that's not confirmed.
Finally, it's said that internal WWE talks about Bill Goldberg returning for Wrestlemania 27 are cold right now