GLENDALE, Ariz. — The story of Dane Dunning’s season-ending elbow sprain presents the way a lot of pitcher injuries do: a tough, hard-nosed innings-eater who has distinguished himself from an early age for his competitive nature and work ethic feels a twinge of pain in his elbow.



In this case, it was a feeling after he would throw his first curveball in the bullpen before his start … and then it would go away. And because it went away for the rest of the night, and because he could still pitch, and still contribute to his team, and because he’s accomplished so much in his career by pushing himself harder than his peers, he kept throwing.



The twinge of pain happened again and again, but it still never advanced beyond a small concern at the start of his warm-ups, as the 23-year-old continued to distinguish himself as one of the best starters in Southern League. He struck out 10 in eight scoreless innings in his last start before the...