Brock Lesnar is not expected to wrestle for WWE again until Survivor Series, which takes place in November. There had been some rumors that WWE burned though nearly all of Lesnar's dates that he was originally contracted for but that doesn't appear to be the case. The latest word is that Lesnar still has plenty of dates left on his WWE contract and the company should have no problem booking him for several more feuds, including one at WrestleMania 29.
As seen at WWE SummerSlam last night, Triple H was seen telling the crowd "I'm Sorry" after his match with Lesnar. The pay-per-view ended with Hunter walking sadly to the back, continuing to apologize and looking like he was about to cry. Michael Cole asked "You have to wonder .... is this the end of Triple H?" and Jerry Lawler saying "Wow, I think he just said goodbye".
In an update on this, there are no plans for Triple H to retire from in-ring competition. He'll be wrestling in "big time" matches and only on a part-time basis as he has been doing as of late. You likely won't see Triple H wrestle again until later this year and then again at WrestleMania 29.