Because he still has an option year, I think the Twins hang on to Kirilloff one more year. Except for a sharp first half of April, he did not perform well, that is a fact. The Twins are almost certain to part ways with Max Kepler, meaning there will be room for another corner outfield left handed bat.
IMHO, AK's predicament mirrors Trevor Larnach's coming in to this year. He won't have a place to play unless there is an injury or someone really slumps and may have to go to the minors to await his chance. Also in Kirilloff's favor is that top prospect Emmanuel Rodriguez has missed two thirds of the season and didn't get out of AA, so he is at best a midseason prospect for promotion. If the Twins do re-sign Santana, that will close another door on Kirilloff's future as a Twin.