Raiders running back Latavius Murray exceeded 1,000 yards and made his first Pro Bowl last season. Yet, by Murray’s standards and many others, the Raiders rushing attack wasn’t good enough.

The fourth-year pro expressed disappointment in the ground game, and head coach Jack Del Rio echoed those sentiments at the NFL Scouting Combine.

The Raiders addressed it during free agency by signing elite offensive guard Kelechi Osemele and re-signing left tackle Donald Penn.

The next step is adding options carrying the ball. Murray took 72 percent of his team’s carries, a whopping total of 266. There’s no doubt the Raiders could use some help.

That hasn’t happened yet.

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A fortnight’s passed since free agency began, and the team’s backfield depth chart remains unchanged. Taiwan Jones and Roy Helu are behind Murray, despite being ineffective last season. Jones had ball security issues, and Helu never caught on after early injuries and hip ailments that required offseason surgery.

Raiders general manager Reggie McKenzie said Monday at the NFL owners meetings fresh blood is on the way.

“We had some injuries there, both backups Helu and Tawian were injured. We need some healthy bodies back there to help out,” McKenzie told CSNBayArea.com’s Matt Maiocco. “The way this league is with the pounding you’re taking, you can’t just have one guy getting beat up all year with no help. We’ll get some help. We’ll get healthy. We’ll see how it goes. It’s March, so we have some time.”

The Raiders reportedly showed interest in unrestricted free agents Chris Ivory and Doug Martin, though those players signed relatively big money deals with other teams.

Second tier options remain on the free agent market, and there are quality alternatives in the NFL draft. Some experts have suggested Ohio State’s Ezekiel Elliott could be an option at No. 14 overall. The Raiders could find value later the draft as McKenzie did with Murray, a sixth-rounder from 2013.

Desire to keep Penn ‘never wavered’

The Raiders re-signed left tackle Donald Penn last week, a happy ending to a process that took a bit longer than the player hoped. Penn hoped to re-sign early in the offseason, but the sides couldn’t agree on a value. There was pessimism it would happen, prompting Penn to book a trip to New York for a visit with the Giants. A last-minute deal kept Penn in Oakland on a two-year, $11.9 million deal with $5.5 million in guaranteed money.

“I was trying to sign him during the season, so that never wavered,” McKenzie said. “If he’d gone somewhere else, that would’ve been the only thing. But we’ve always wanted him back.”

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Mario Edwards Jr. update:

The Raiders are still taking a wait-and-see approach with young defensive lineman Mario Edwards Jr., who suffered a strange neck injury near last season’s end. An exact diagnosis hasn’t been given, though significant concern about the player has been expressed since the injury occurred.

McKenzie suggested in February that Edwards Jr.’s injury might’ve been genetic, something that was compounded when he got hurt. Edwards Jr. is confident he’ll return and play well, though the Raiders are giving last year’s second-round pick time for further evaluation.

He’ll be reexamined in April.

“He’s rehabbing. He feels great so that’s a good thing, but we’re going to wait and get all the information and get with the doctors,” McKenzie said on Monday. “We have another month for him to go by and see, listen to what he has to say, and we’re going to take it one day at a time.”

The Raiders offseason program begins April 18, which OTAs and practices set to begin in May.