ALAMEDA, Calif. -- While Amari Cooper being ruled out for Sunday's game against the Dallas Cowboys after the receiver re-injured his left ankle wasn't much of a surprise, the same can't be said of the Oakland Raiders putting rookie safety Obi Melifonwu on injured reserve Friday.
Melifonwu, who began the season on IR because of a knee issue that developed during training camp, underwent surgery on a hip injury Thursday, Raiders coach Jack Del Rio said. The second-round pick did not appear on an injury report with the issue until Wednesday.
Del Rio would not say when Melifonwu's latest injury occurred, though he made his NFL debut at Miami on Nov. 5.
The safety started at left cornerback in Mexico City against the New England Patriots two weeks later, with dreadful results, and then saw his playing time dwindle, from 26 defensive snaps against New England to one against the Denver Broncos to none against the New York Giants and Kansas City Chiefs.
With Melifonwu joining first-round selection Gareon Conley on season-ending IR, the Raiders got 14 total tackles and one pass defensed in seven total games this season out of their top two draft picks.
The Raiders activated cornerback Antonio Hamilton off IR.
"I can't tell you exactly when that occurred," Del Rio said of Melifonwu's injury. "I think it's been a little bit that he's been working with. It required surgery, he had it, so he'll be out."
Del Rio was more positive about Cooper's prospects, however, after Cooper saw his left ankle rolled up on last weekend while serving as a lead blocker on a sweep play at Kansas City.
And you have to wonder if the Raiders regret suiting him up against the Chiefs.
"I think he's better than he was, but he's going to be out this week," Del Rio said. "I think we have a chance to get him back.
"We'd rather not focus on what we're not getting and focus on what we can do with the guys we have. That's how we've approached it. He's not practiced all week and we're ready to move on."
"He's a good player, but we don't dwell on that," Del Rio said. "We go with the next guy up. The guys have been working hard, coming together, playing faster with more certainty and that's what we're looking for."