As mentioned earlier in the quoted interview, Gawanke was pretty adamant he doesn't want to go back the AHL with the Manitoba Moose again. He's played there for 4 years without getting any looks in the NHL and felt the time he had put in meant he deserved a chance over others.
He's an offensive RD with a good shot (20 goals last season), I think if Karlsson gets traded (and opens up an RD spot), it would seem much more likely he'll give it another shot on a two-way deal.
If Karlsson stays, and he sees any threat for being at least RD #4 in the system (Karlsson-Benning-Burroughs-Gawanke), he likely won't go for it.