According to PWInsider.com, WWE Superstar Kane was the guest on Kare 11 (NBC) this morning, and may have let slip that Brock Lesnar would be at this weekend's WWE Elimination Chamber PPV. The interviewer asked how Brock Lesnar fit into the current plans, and if he was still with the company. Kane said that Brock was still with the company, and that he would be at Sunday's event.
That being said, the interviewer was apparently not current with the WWE product, and thought Kane was in the Elimination Chamber match itself, so he could have just been ending the interview, or intentionally tossing around misinformation. Brock Lesnar has not been seen since the Royal Rumble PPV in January, where he defeated the Big Show, but he is expected to make his return soon to build up towards WrestleMania. Given that the Elimination Chamber is in Brock's hometown, it seems as good a place as any. If not, it's almost certain he will be on Monday's huge episode of Raw.