It's followed by this:
As little is left to the discretion of the players on the field as possible. They are tools, or rather of a mechanism run by a 'mastermind' who sits on the bench. Batter and fielder mechanically carry out motions whose plan and purpose are established for them・・・・・The beauty of baseball, indeed, is precisely in its mechanical perfection. It is related to the beauty of a machine, rather than of art.
With this context, how would you paraphrase the phrase 'the machine of players'?