Allard is pretty much batting practice to opposing hitters like Walker at this point. He got lucky with BABIP his first couple of starts but really presents no advantage either and like Walker is not used to pitching out of the bullpen.
The main point is that mediocre relievers are better suited for the last pitching spot, especially in a short series. And if that means a Lazar has to suck up 2+ innings to save the staff then so be it. He'll be happy with his playoff winnings no matter what.