Complex sentence: Roundtree started playing football on the Pee-Wee Dayton Flames from first grade to junior high along with Michigan teammate Michael Shaw, who because he was eight months older than Roundtree played in a different level.
Split into simpler sentences: Roundtree started playing football on the Pee-Wee Dayton Flames in first grade. He played on the team until junior high, joined by his Michigan teammate Michael Shaw, who, because he was eight months older than Roundtree, played in a different level.