First off, nobody's talking about cutting Hays. The worst that'll happen is he gets sent down to AAA to work on things.
Second, guys in slumps do actually get DFA'd all the time if the slump lasts long enough. The question is at what point does a slump become the new normal? Sucking eggs for 10 or 20 games is a slump. Hitting .209 / .270 / .332 over 95 games and 316 ABs wouldn't normally be considered a slump. Hays has been worse than Mateo over that period, and people here were rending garments over Jorge's pathetic offense last year. Since the third week of June last year Austin Hays has been worse offensively than Joey Rickard, Caleb Joseph, and even Austin Wynns were when they played for us. How long did their slumps last?