Oakland Raiders wide receiver Antonio Brown is working out with first-round draft pick Trayvon Mullen in South Florida according to an Instagram post by Brown.

This is only one route, but it looks Mullen is doing an excellent job of keeping up with Brown who has some of the best speed off the line in the league.

There was a lot of criticism while Brown was with the Pittsburgh Steelers that he wasn't a team leader, but this appears to show different with Brown leading team workouts away from the team facility.

Mullen was the Raiders second-round pick in April going 40th overall, and the expectation is that he will be a solid player that could play an impact as early as this season.

Coming into the draft Mullen was praised for the ability to run with vertical receivers, but was criticized by ESPN for not being smooth.

He has good height with adequate bulk but shorter arms and average top-end speed. He's a smooth athlete with good length. Mullen shows the ability to open his hips and run with vertical receivers, but he's not as sudden as he is smooth. His instincts and recognition skills need to improve. He struggles a bit with leverage as a zone defender. Mullen's ball skills are better than his ball production indicates and he does a solid job on 50-50 balls. He gives decent effort in run support and has adequate tackling skills but he's not very physical or aggressive. Mullen's well-respected and a leader in the DB room with a good work ethic.

Going against one of the best receivers in the league should help Mullen improve his game, and do that quickly.