Complex sentence: He was given the number 22 jersey for the 1993-94 season, but failed to make any more appearances for United after he suffered a broken leg, and was allowed to join Port Vale on a free transfer in August 1994.
Split into simpler sentences: He was given the number 22 jersey for the 1993-94 season, but did not make a single appearance for United. Soon after, he suffered a broken leg, and was allowed to join Port Vale on a free transfer in August 1994.