ABC’s Jonathan Karl says his GOP sources are telling him that Marco Rubio isn’t going to be Mitt Romney’s running mate.

Even before the Republicans chose a presidential nominee it was widely assumed that Sen. Marco Rubio, R-Fla., would be at the top of anybody’s list of vice presidential candidates. The reasons are obvious: Not only is he young, charismatic and wildly popular with conservatives, but he could also help Republicans win a key state (Florida) and make inroads with Hispanics.

But knowledgeable Republican sources tell me that Rubio is not being vetted by Mitt Romney’s vice presidential search team. He has not been asked to complete any questionnaires or been asked to turn over any financial documents typically required of potential vice presidential candidates.

This afternoon Romney announced that his campaign was “thoroughly vetting” Sen. Rubio, contrary to ABC’s report.