ALAMEDA – Rookie Neiron Ball earned an important role on this Raiders defense, as an athletic coverage linebacker on passing downs. He was productive against opposing tight ends, a defensive weakness before his emergence, and proved a strong pass defender with potential for more responsibility.

Against the Denver Broncos, at least. A knee injury will temporarily keep him from stacking performances together.

He suffered a knee sprain in the first half of Sunday’s victory over the San Diego Chargers, and had an MRI on Monday afternoon. The Raiders initially feared the worst, that his season might be over, and got somewhat better news.

“It’s unfortunate Neiron got hurt,” Raiders GM Reggie McKenzie said. “It’s not as bad as some had thought. We expect him back.”

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McKenzie likened Ball’s situation to edge rusher Benson Mayowa, who suffered a knee sprain in the preseason finale versus Seattle and missed the season’s first four games.

Ball will miss some time, meaning Ray-Ray Armstrong and Curtis Lofton will re-enter as linebackers on passing downs. Neither player fared well in that role, which led to Ball seeing more snaps. Armstrong was the main contributor after Ball went down against San Diego, and allowed four receptions for 52 yards and a touchdown. Armstrong had largely been phased out of the defense prior to that game.

Ball, a fifth-round pick from Florida, will also be missed on special teams. The Raiders hope he won’t be gone too long.

“Hopefully we get him back sooner than later,” McKenzie said.