A press release on Blue1's Finnish language website tells that Blue1 will receive their own MD90s during the summer.
The first of total number of three has already started traffic on June 26th and the two others will join the fleet before beginning of September. Until then part of the MD90 routes will be operated with aircrafts and crew leased from Nordic Airways.
I heard from my brother-in-law that these Nordic-aircrafts are not quite the standard one could expect from Blue1. As he put it "I would never have wanted to step into this aircraft if I didn't trust that also the crew wanted to get home safely."