Ryoto Igarashi (see NBPT profile and vids) is intent on pitching in the majors next year. The 30yo reliever has a plus fastball (93-96+97) and a forkball (86-89) - see velo chart on his 8/12 appearance. He had TJ surgery in 2006 and his command will likely prevent him from closing but he appears to be a guy who has the stuff to be a set up guy to compliment CJ.
I assume that CJ will co-close again next year given FF's injury issues and the fact that he pitched in 1/3 of the team's SVOs - the CJ to starter rumors seem like so much hot air. Though I will say that it is a bit weird that Feliz has yet to pitch in winter ball but he only needs about 20-30 innings to get stretched out enough to be considered for a starting role next year. I expect that he is getting stretched out and will appear around mid-November.