Based on the number of pilots they have hired the last year, and continue to hire, I would predict they are planning on putting smaller airframes at the mother ship. I am not sure what size airframe.
The regionals can't hire, so putting these jobs at the mainline makes the jobs more attractive. Hiring them from the regionals at new hire longevity is cheaper and easier than buying the regional and merging pilots at their regional longevity.
Just a guess.