Sagbo might not have the best ability in the world, but while Jelavic is out, we have no other 'hold-up' options. Jay Simpson wasn't a great striker, but he played an important role in our last promotion season as he held the ball up and brought others into play - he wasn't the best footballer, but was the best person we had available to do that job, so he got picked. While Jelavic is out, the same should apply to Sagbo.
I agree with dazzar, with no other options available to us, I'd have recalled Sagbo, Hernandez is useless as a lone striker.
