I disagree with all of you.
I'm pulling for the Brewers (of course--they are the anti-Cubs right now), and I am a Sabathia fan. But I agree with the OS's explanation that that play would have to have been "above average" to get the runner. If he had fielded the ball cleanly, he probably would have gotten the runner out, but the fact that he had to leave the mound, run up, whip around, and make a good throw removes the question of whether the runner would have been out.
And again, I am rooting for the Brewers, but Ned Yost was his usual crybaby self about the whole thing. Hmmm..... with all due respect to the Mets, it makes one wonder if this has anything to do with why they haven't won a game since then.
ERROR. Plain and simple. If he "fielded the ball cleanly", and then made a bad throw, this would be another discussion. This one ends with the bold print above.