Aroldis chapman has value in that he'll help your ratios, especially in a roto league where there is a max innings cap. He'll post 100+ strikeouts in limited innings.
Drabek has the upside to win rookie of the year, but you need to pick up Bumgarner. He could enter elite territory as soon as this year.
Keeper League:
F) N.Backstrom, E.Malkin, V.Lecavalier, P.Mueller, A.Mcdonald, B.Boyes, A.Hemsky, S.Horcoff, K.Turris, D.Jeffrey, M.Perreault, C.O'Reilly, S.Upshall, M.Erat, S.Gagne, D.Legwand D) S.Souray, M.Streit, A.Babchuk, T.Gilbert, I.Cole, J.Hillen, M.Methot G) B.Elliott, S.Varlamov, C.Ward, J.Reimer P) N.Kadri, E.Kuznetsov, S.Shirokov, V.Tarasenko, J.Blum, OEL, J.Moore, O.Pavelec