Ruddy-faced and taciturn, Yost looks like a baseball manager from a less image-conscious era, someone who might spend the game with tobacco juice dribbling down his chin. ‘‘He’s not reading psychology books,’’ says Jonah Keri, a writer for Grantland. One manager who actually does read them, the Cubs’ Joe Maddon, is widely considered baseball’s best. Maddon wears hip black-rimmed glasses and collects wine. The Yankees’ Joe Girardi, engaging and articulate, has an engineering degree from Northwestern, which presumably helps him interpret the mathematics used to capture what’s happening on the field. Brad Ausmus, who has managed the Tigers the last two seasons, studied government at Dartmouth.

Yost grew up in California’s Livermore Valley as an undersize striver seeking a sport in which he could excel. Cut from the high-school soccer team, he struggled for a semester as a 5-foot- 2 hurdler. Then he turned to baseball, which he hadn’t played since Little League. In 36 J.V. at-bats as a sophomore, he couldn’t muster a hit. Nevertheless, Yost decided he was going to play — not merely in high school, but for a living. ‘‘I just knew it,’’ he says. ‘‘When I sat down with my counselors and they said, ‘What are you going to do?’ I said, ‘I’m going to be a professional baseball player.’ And they looked at me like I was nuts.’’

Such certitude, based on no discernible foundation, has informed Yost’s decision-making processes all his life. ‘‘I often wonder, Do other people have that same feeling and then it doesn’t happen?’’ Yost told me. ‘‘Because I knew it was going to happen.’’ He made varsity, had a growth spurt, then landed at Chabot College. After he starred on a summer team, the Mets drafted him as a catcher. In 1980, he reached the majors, just as he had predicted. He seldom played, though. Over six seasons, Yost accumulated just 605 at-bats, a number that starters can exceed in a single year. He was wondering what to do next when the Braves asked if he would work with young players at their minor-league outpost in Sumter, S.C. He ended up as the manager there for three years before being hired onto Bobby Cox’s staff in Atlanta, where he remained for more than a decade as a bullpen coach and later a third-base coach.

Along the way, he cultivated an unconventional relationship with players, one that made them eager to get to the ballpark. ‘‘He’d throw a belt into the whirlpool when I was in there and pretend it was a snake,’’ recalls Eddie Perez, who was in Sumter and Atlanta with Yost. ‘‘Not many managers would do that.’’

Yost can be prickly in news conferences. But in an intimate setting, he’s engaging, even warm. One afternoon this summer, he shared memories with me about a friend he considered a mentor, the car racer Dale Earnhardt, whom he met through a common friend in the early 1990s. Yost wears his No. 3 to honor Earnhardt, who died in a crash in 2001. ‘‘We hit it off,’’ he said. ‘‘Hunted together every year.’’ In 1994, when a labor dispute truncated the baseball season, Earnhardt invited Yost to travel with him on the Nascar circuit and serve as ‘‘rehydration engineer’’ (in other words, water-fetcher). At one race, Earnhardt roared back from a huge deficit and nearly won. When Yost congratulated him, Earnhardt grabbed him by the shirt and pulled his friend nose to nose. ‘‘Never, ever, let anybody who you’re around, anybody you’re associated with, allow you to settle for mediocrity,’’ Yost says Earnhardt told him.

Later, Yost would be criticized for not replacing erratic infielders when he had late-inning leads and allowing untested pitchers to compete — and often fail — in crucial situations. The critics didn’t understand, he told me, that he wasn’t necessarily trying to win those games. ‘‘The difference between 72 and 76 wins doesn’t mean a damn thing to me,’’ he says. It was the same as the difference between second place and last place, which, Earnhardt had stressed, was no difference at all.