IMPROBABLY UNSTOPPABLE A baseball season defined by pitching excellence took another fascinating turn on Friday when Edwin Jackson of the Arizona Diamondbacks threw the majors’ fourth no-hitter this season. It was, perhaps, the most improbable no-hitter in years. Facing one of his former teams, the Tampa Bay Rays, Jackson allowed eight walks in a 1-0 victory at Tropicana Field. In an era marked by rigid adherence to pitch counts, Jackson threw 149 pitches, the most in the majors since 2005.