Complex sentence: Having topped the bowling averages in local competition, Marsh was then selected to make his debut in the Sheffield Shield, where he made an immediate impression and led the first-class bowling averages for the season after three matches.
Split into simpler sentences: Having topped the bowling averages in the local competition, Marsh was selected to make his debut in the Sheffield Shield. He made an immediate impression and led the first-class bowling averages for the season after three matches.