Persistence is key in the NFL which is why the Oakland Raiders have not given up their pursuit of DeMarco Murray in free agency.

The NFL's leading rusher may be heavily linked to the Philadelphia Eagles, but the Raiders are determined to stay in the hunt. They have significantly more salary cap space than the Eagles and can offer him more playing time assuming Ryan Mathews officially signs with Philly.

The Jacksonville Jaguars have been mentioned as a possible landing spot as well, though ESPN Raiders reporter Bill Williamson maintains that Oakland, Dallas and Philadelphia remain the front runners.

The Raiders ranked last in the NFL in rushing in 2014, managing a measly 77.5 yards per game on the ground. Though coaches like third-year back Latavius Murray, he is still unproven. With Darren McFadden unlikely to be re-signed in free agency and Maurice Jones-Drew retiring, Oakland finds itself with a glaring hole in the backfield that must be addressed this offseason. It would not be surprising to see Oakland up its offer at the last minute to try and guarantee Murray's signature on the dotted line.

Murray is coming off the best season of his career. He led the NFL with 1,8845 yards and 13 rushing touchdowns. He also caught 57 passes for 416 yards. One reason why potential suitors should be wary, however, is Murray's injury history. He missed 11 games through his first three seasons and suffered a broken bone in his right hand last year. Murray's talent is undeniable but coming off a season in which he approached 450 total touches, any team that signs him should have a viable backup in case he misses time.

The Raiders are also meeting with Cincinnati tight end Jermaine Gresham and are confident that they can reel him in.