Complex sentence: He was not a full time starter at quarterback until his senior year when he threw for 1,600 yards and twelve touchdowns while leading Davis to a 6-2-1 record and the Delta League championship.
Split into simpler sentences: He was not not a full time starter at quarterback until his senior year when he threw for 1,600 yards and twelve touchdowns. He led Davis to a 6-2-1 record and the Delta League championship.