Complex sentence: Christensen began his NFL career as a second round draft pick of Dallas in 1978 out of Brigham Young University, while playing fullback he broke his foot in the final exhibition game that year and was cut.
Split into simpler sentences: Christensen began his NFL career as a second-round draft pick of Dallas in 1978 out of Brigham Young University. While playing fullback, he broke his foot in the final exhibition game that year and was cut.