From the other angle he clearly starts his slide before the bag. It's late, but before the bag. He's in the baseline, and his hand is heading straight for the bag when he takes a knee to the face.
I don't think he expected Tejada to come back that way because he didn't even put his hand up to protect his own face.
In case you weren't aware, he broke his right leg. It was a completely freak thing. His cleats weren't even stuck in the ground like Scutaro's when Holliday rolled up his leg. That was damned near a choir boy slide compared to those other ones posted.
I also think Mattingly sat him because of this, regardless of the appeal on the suspension. Why else do you not play an offensive 2B against the Mets he's faced more than anyone else on the team? I'm also not surprised there's talk of firing Mattingly.