on Kirilloff - Hey, I don't like it, but I can also understand that it becomes a matter of how he fits into the lineup and batting order.
Kirilloff can play some corner OF, but his best defensive position is 1B. right now, the Twins have Arraez - the leading hitter in MLB - as their primary 1B.
move Kirilloff to the OF, and you are benching either Larnach or Kepler. Both of those players have been solid - and they're all left-handed hitters, so you gain no positional advantage.
I guess you could bring him up to be the DH against RHP, but I suspect the Twins would prefer for him to be an every-day player.
and Kirilloff is a left-handed hitter. the Twins are a fairly left-handed heavy team already. That is one reason why Miranda has stuck around - a RH bat (especially with Garlick out).
It's not as simple as "just bring him up." because every move has a ripple effect on the roster and batting order.