Offensively, the only real difference this year from prior years for Nyjer is a .050 point drop in BABIP. That is what drove down the OBP from .350 to .310. His walk rate and K rate are the same as his career MLB averages (7% / 17%). he is fast. There is little reason not to expect him to get some of his BABIP back. He is probably not a good leadoff hitter, but he is also probably not a bad 7th or 8th guy, either.
I agree that he isn't as bad as he has been this year. But I also think his ceiling is probably Juan Pierre, who isn't very good. And as a CF, which is a premium defensive position, he isn't outstanding. He's fast but he gets picked off too much to make his steals benefit the team.
Of course, as I say that, Morgan makes an amazing defensive play. That notwithstanding.