Signed up to post about Warren as well, glad someone else noticed.
It looks like a he was a decent reliever from 13-14, a decent reliever/starter in 15, and a bad 2nd half reliever with the cubs last year after a good 1st half with the Yankees. He's back to the Yankees now. His career numbers are ok...3.58 ERA, 1.25 WHIP, 7.6 K/9, 3.1 BB/9.
Both Yankees starters were pulled early this year, and he came in a pitched 2.1 innings in both games. I'll keep a close eye to see if they use him like the Astros use Devenski, but not ready to pounce yet.