imho the situation here is quite normal for basketball in europe, the player usually have contract for the saison who expand for the Playoff where there usually earn more with bonuses.
The staff have a year contract since PR work is done during the offseason too, and trainer prepare and plan the upcoming season. And for the doctors, they are usually busy in the offseason, since many pro wait till off season till there get there threatment and work with painkillers during the season.