Complex sentence: Bravo started his career playing in the inferior leagues with LDU Quito, after he became 17 years old he left LDU Quito and was moved in to the Emelec the third most important team in the Ecuadorian first league.
Split into simpler sentences: Bravo started his career playing in the inferior leagues with LDU Quito. At age 17 he left LDU Quito and moved to Emelec, the third most important team in the Ecuadorian first league.