Ba absolutely had to go off when he did. He looked absolutely gone from the 50th minute, for whatever reason.
I can see his reasoning behind not risking Ben Arfa or Marveaux against thugs, but Sammy surely would have given us a decent outlet, which is what we desperately needed in the last 20 minutes of the game.
That said, he deserves massive credit for the first half. We were absolutely splendid. Great to watch and got the goals.