Complex sentence: His show of promise playing with Mckeesport team carried over until 1910 when he was split duty serving as a player for the Flint Vehicles, who were established with the Southern Michigan League.
Split into simpler sentences: His show of promise playing with McKeesport team carried over until 1910. During the 1910 season he split duties, also serving as a player for the Flint Vehicles, who were established with the Southern Michigan League.