While it kind of makes my timing suck on the earlier post speculating on why WWE hasn't more directly addressed her absence, if the report from The Wrestling Observer is true, it does make you wonder why they were so low key about her being gone if they knew she'd be back in a month and a half.
That report says that former Divas champ AJ Lee will be returning to WWE after Extreme Rules for their annual tour of the United Kingdom and Europe, eventually leading to a feud based around her rematch clause against either Paige or Tamina, whoever holds the butterfly belt after the next "special event".
Regardless, the same research that pointed us to a hiatus for Batista this summer also backs up The Observer's story. AJ is advertised for shows starting with the May 14th house show in Glasgow, Scotland, and thoughout the tour of Europe, including the May 19th Raw taping in London. Her first appearance on an advertisement for a show taped in the United States doesn't appear to be until the July 14th Raw from Richmond, Virgina, which would be the "go home" show for Battleground.
Of course, every card comes with a "All Superstars Subject to Change" disclaimer, so if Dave Meltzer and company are working off of the same research that I just did, this could all be derived from a marketing person not getting around to updating a few web pages yet.