Complex sentence: Many players travel considerable distances to practice with, and play for one of the mentioned teams, as player numbers are too to support teams in the smaller cities and country-side of the Republic of Korea.
Split into simpler sentences: Many players travel considerable distances to practice with, and play for one of the mentioned teams. This is due to the fact that the pool of players are generally too small to support teams in the smaller cities and country-side of the Republic of Korea.