Raiders place 2nd-round S Obi Melifonwu on IR

ALAMEDA, Calif. (AP) The Oakland Raiders invested plenty of draft capital in boosting a secondary that allowed more big pass plays than any other NFL team a year ago.

Now that they have a chance to show off how those changes will improve the defense in the season opener on Sunday at Tennessee one of those players will be on the sideline recovering from an injury while the other's status is unknown.

The Raiders placed second-round safety Obi Melifonwu on injured reserve on Tuesday, forcing him to miss at least the first eight weeks of the season with a leg injury.

Meanwhile, first-round cornerback Gareon Conley hasn't taken part in a full practice since June because of a shin injury and is running out of time to get up to speed for the opener against the Titans.

Conley had his first limited practice last week and took part in a walkthrough Tuesday. He has three practices left before the opener.

Conley and coach Jack Del Rio were unavailable for comment.

The Raiders did get some good news in the injury front in the secondary when cornerback David Amerson was cleared to practice after sustaining a concussion in the third exhibition game.

With Conley's long absence and Sean Smith's struggles in the preseason and training camp, Amerson is the surest bet in what is otherwise a suspect secondary.

''Right now we're really polishing things up and getting ready to go to war,'' Amerson said. ''Hopefully it's to the standards we know it should be.''

The Raiders allowed an NFL-worst 61 pass plays of at least 20 yards last season and made a focus this offseason on fixing those issues. They drafted Conley and Melifonwu and also brought on former Chargers defensive coordinator John Pagano as a defensive assistant tasked with improving the communication on the back end.

After some shaky moments in the preseason, Amerson is pleased with the progress he's seen of late and hopes the defense won't drag down quarterback Derek Carr and the high-powered offense.

''Just as an athlete and your competitive nature, you always want to be the best,'' Amerson said. ''We have a defense full of guys that feel like they want to be the best at their position and the best defense. It's more than just words. I feel like we've been putting in the work and it's show time on Sunday.''

The Raiders also placed offensive lineman Denver Kirkland on injured reserve Tuesday with a leg injury. Kirkland and Melifonwu will both be eligible to return to practice in six weeks and be activated to play games in eight weeks if Oakland chooses to use its two designations for return on the two players.

NOTES: The Raiders signed S Erik Harris and LB Xavier Woodson-Luster to the active roster. Woodson-Luster was released by Oakland and Harris was let go by New Orleans on cut-down day Saturday. Harris, who played last season for the Saints, was about to board the plane for a tryout in Buffalo when he got the call to sign with Oakland. ... K Sebastian Janikowski declined interview requests a day after an ESPN report that the team was considering cutting him after 17 seasons if he didn't take a pay cut. Janikowski was guaranteed his Week 1 salary by being on the roster Tuesday and will be guaranteed his full $4.05 million salary for 2017 if he is on the roster Saturday.

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AP NFL website: www.pro32.ap.org and http://twitter.com/AP-NFL

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