For me Burnes, GRod, Bradish, Means and Kremer are starters. Wells, Irvin and Suarez are spot starters/relievers that can give the O's 3 to 4 innings when needed.
I think Kimbrel needs a couple of days off between closer appearances. The other two games Irvin, Suarez and at some point Wells can pitch the 7th through the 9th. Cano, Coulombe and Perez filling in relief innings.