Complex sentence: Smith sustained a concussion in the middle of the 2012 season and was replaced by Colin Kaepernick, despite posting strong statistical numbers during the year, Smith couldn't regain his starting position after he was medically cleared to play.
Split into simpler sentences: Smith sustained a concussion in the middle of the 2012 season and was replaced by Colin Kaepernick. Despite posting strong statistical numbers during the year, Smith couldn't regain his starting position after he was medically cleared to play.