tatropāhūya gopālān
kṛṣṇaḥ prāha vihāra-vit
he gopā vihariṣyāmo
dvandvī-bhūya yathā-yatham
tatra -- thereupon; upahuya -- calling; gopalan -- the cowherd boys; krishnah -- Lord Krishna; praha -- spoke; vihara-vit -- the knower of all sports and games; he gopah -- 0 cowherd boys; viharishyamah -- let us play, dvandvi-bhuya -- dividing into two groups; yatha-yatham -- suitably.
The word yatha-yatham means that Krishna 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.