If Alex Van Pelt (the Browns' OC) is to be believed, OBJ is a complete WR - including blocking.
From this article: [
touchdownwire.usatoday.com]
The other stuff that he does and in the run game, I know it is not sexy, but he is really effective and he really came down and really put the wood on a couple of those safeties in the game. He does a lot of great things other than catching the ball on the field ...And this, from the same article:
Beckham’s coaches and teammates in Cleveland also praised his effort as a run-blocker ...
AlbaNY_Ram