Complex sentence: In 2012, Zito relied mostly on his two-seam fastball and cutter, and reduced his reliance on the four-seamer, which was the slowest four-seamer in MLB among starting pitchers that year, at 84.6 mph.
Split into simpler sentences: In 2012, Zito relied most on his two-seam fastball and cutter, and reduced his reliance on the four-seamer. In the 2012 season, Zito had the slowest four-seamer in MLB among starting pitchers, at 84.6 mph.