Helu, 26, spent the last four seasons with the Washington Redskins. He rushed for 216 yards on 40 carries in 2014.
Helu made more of an impact as a receiver out of the backfield. He was 12th among running backs with 42 receptions in 2014 and ranked fourth with 477 receiving yards.
The only Raiders running back currently under contract for next season is Latavius Murray. Darren McFadden is a free agent and Maurice Jones-Drew announced his retirement. Oakland is also said to be in the running for DeMarco Murray.
- Dan Gartland