tatropāhūya gopālān
kṛṣṇaḥ prāha vihāra-vit
he gopā vihariṣyāmo
dvandvī-bhūya yathā-yatham
tatra - thereupon; upāhūya - calling; gopālān - the cowherd boys; kṛṣṇaḥ - Lord Kṛṣṇa; prāha - spoke; vihāra-vit - the knower of all sports and games; he gopāḥ - 0 cowherd boys; vihariṣyāmaḥ - let us play, dvandvī -bhūya - dividing into two groups; yathā-yatham - suitably.
The word yathā-yatham means that Kṛṣṇa naturally wanted the two teams to be evenly matched so that there would be a good game. In addition to the pleasure of sporting, the purpose of the game was to kill the demon Pralamba.