Major League Baseball is expanding its investigation of Yankees superstar Alex Rodriguez by adding the pitch-tipping allegation spelled out in Selena Roberts' new book A-Rod to the agenda, people familiar with the inquiry told SI.com. ...

MLB's burden of proof in a case like that would have to be extremely high to take action; they'd need either Rodriguez to admit to the charges, or for someone else intimately involved to swear to it. It would seem futile to go over video of the games and try to match up alleged tips and pitches, especially since ex-Rangers teammates have come forward to say they didn't notice any tipping, and they were there.