To Hicklen's credit, he's forcing the issue. The problem right now is figuring out the 40-man roster spots for the pitchers coming back from the 60-day IL first.
D.L. Hall is ready to come back, Ross just had his first rehab start (it was his back, not his arm, so I assume a quick ramp-up for rehab appearances), and Devin Williams will be back soon. So who are the three who get DFA'd? Herget, Capra (assuming Ortiz is back from the IL soon), and then one of Zastryzny, Keuchel (not until Ross is back), or possibly Junk? Maybe Haase once Sanchez is back, but do you risk losing your catching depth if they DFA him? Then you potentially have Bukauskas coming back, that's another spot. Then you have possibly adding another pitcher at the trade deadline.
For Hicklen to be added, that means DFA-ing perhaps all three of Zastryzny, Keuchel, and Junk to make room for him. I don't see that happening until September 1st when they can add another position player as it will likely take until then to sort the pitching out.