fWIW, the active roster lists 10 pitchers: Gore, Irvin, Parker, Lord (4 starters), Ferrer, Pilkington, Rutledge, Brzykcy, Lara, and Henry (6 relievers). It lists 2 catchers, 7 infielders (including Bell, with DeJong and Tena), and 3 outfielders. So, 3 pitchers and an outfielder need to be added. Folks here have said Hassell is one of the call ups but it's not in the transactions yet.
The 40 man has Hassell as the sole minor league outfielder (Crews on the 60 day IL). Baker, Chaparro, Lipscomb and Nunez are the 4 minor league infielders. Keibert is IL-7 but counts against the 40 man. There are 8 40-man pitchers in the minors: Beeter, Cavalli, Eder, Loutos, Ogasawara, Ribalta, Salazar, and Thompson. Williams, Law, Herz, and Gray are 60 day IL.
So, with 22 on the active roster and another 14 on the 40 man in the minors, that's 36 total. Means they have 4 open slots on the 40 man.