@Huber.
Baseball has never set a minimum or maximum for any position, teams though would carry what made sense via the era of the game. Modern game carried more pitchers than previous era’s.
Most teams setup with at least 12 pitchers and at least 12 position players then the last one is usually a float between guys with options. Francona liked to always have 13 pitchers, while many National league teams always like to keep an extra bat for pinch hitting. (Bobby Cox at times would have a person, that is essentially what he did was just pinch hit in a sense if I recall right).
Now with the 26 man roster, Francona can keep his 13 pitchers but now he can keep 13 position guys as well. 5 starters, 8 bullpen guys.
For the 13 positions players, the locks will likely be
Santana, Hernandez, Lindor, Ramirez, Perez, Leon, Mercado, Luplow, DeShields, Reyes,
So that leaves 3 guys for the last spot, Arroyo is out of options and is a solid defender, so he likely has the utility spot in the INF. OF been discussed, so likely 2 guys get kept there. But don’t count out Freeman and Velazquez since both guys can play in the INF and OF. Velazquez actually by stats, his best position is CF and he is a switch hitter. Chang is an option for the INF, but I think they want him to have everyday ABs. I don’t see Bradley starting the roster out of spring unless he greatly improve his contact rate and walk rate plus Reyes being at least an average OF.