Slowey was a former round six pick by the San Francisco 49ers in 2012 draft out of Western Oregon. He didn't make the team out of camp and the Raiders later signed him to their practice squad last October. He was re-signed to a reserve/future contract following the season.
He was drafted as an offensive tackle but was expected to add depth at the guard position for the Raiders. At left guard, the Raiders have yet to bring back Cooper Carlisle as a free agent and currently have Tony Bergstrom, Jason Foster, and Lucas Nix as those competing for the job to replace him.
There is no word as to why the team let him go at this time and it is still possible they opt to re-sign him before camp. The team's first off-season meeting is April 15.