When Gronkowski arrived for his predraft visit in New England, the Patriots simulated the team’s classroom experience. O’Brien and fellow assistant Brian Ferentz taught him blocking schemes, which Gronkowski absorbed and then demonstrated after ripping off his coat. “We were laughing our asses off, he was blocking the hell out of us,” says O’Brien, now the Texans’ coach. By the end of the meeting, Gronk’s yellow dress shirt was untucked and stained with marker from the grease board. And the Patriots were sold, trading up to get him in the second round, one of Belichick’s shrewdest moves.