Pierson-El caught six of 10 targets for 38 yards and a touchdown in Thursday's preseason win over the Packers.
His seven-yard score in the fourth quarter put the Raiders in position for a game-winning field goal on their final drive of the game, and the second-year wide receiver led the team in catches and targets. Pierson-El remains buried on the depth chart, however, and this performance likely wasn't enough on its own to secure him a spot on the 53-man roster.
Pierson-El signed a contract with the Raiders on Monday, the team's official site reports.
Pierson-El joins the Raiders after spending time with Salt Lake Stallions of the AAF, where he led the team with 36 receptions for 414 yards and one touchdown in eight contests. He also spent time with the Redskins last offseason.