CINCINNATI – Forty-eight hours ago, 30 of the 32 rookie second-round picks still were unsigned, but there has been a lot of movement since then. Cincinnati Bengals second-round pick, linebacker Demetrius Knight Jr., isn’t among those who have signed in the last few days, but the way things are playing out, he should be close. That’s because among the dozen or so recent signings is tight end Elijah Arroyo, whom the Seahawks selected with the No. 50 pick, one after the Bengals took Knight. Per a report from ESPN’s Adam Schefter, Arroyo received $6.872 million of his $8.813 million contract in guaranteed money. That’s 78 percent guaranteed, which sets a baseline for Knight. The whole holdup for