SAN DIEGO — Almost every day, the strangers who stop Nick Kurtz on sidewalks and in restaurants want to talk about the four home runs he swatted one unforgettable evening last summer.They have never brought up the streak.It climbed to 47 games Sunday at Petco Park when Kurtz, the Athletics’ imposing first baseman, collected two singles and a walk in a 5-2 win over the San Diego Padres. No active major leaguer has ever put together a longer single-season on-base streak; likely Hall of Famers Freddie Freeman and Paul Goldschmidt are the next closest, at 46 games apiece. No one has made it to 60 games since Orlando Cabrera in 2006.The record belongs to Ted Williams, who reached base in 84 consecutive games during his second American League MVP campaign in 1949. Kurtz, the 2025 AL Rookie of the Year, is more than halfway there and one game shy of matching Mark McGwire for the A’s single-season record. He recently became the first left-handed hitter in big-league history to amass at least 40 home runs, 100 RBIs and 100 walks in the first 162 games of his career.Unprecedented numbers, along with a 6-foot-5, 240-pound frame, can make it easy to forget he is still only 23.“Whenever you’re being compared to a guy like Ted Williams, you’re doing things that only a handful of people have ever done,” A’s star catcher Shea Langeliers said. “What he’s doing at his age and the maturity that he has and the approach and the mental side of the game, it’s second to none.”Kurtz has prized plate discipline since childhood. He was born three months before the release of “Moneyball.” He has never read the book that reshaped baseball and then business — “I’m not much of a reader,” Kurtz said — but he remembers watching the movie adaptation years ago. In high school, he rarely swung at the first pitch of each plate appearance. When the A’s signed him in 2024 as the No. 4 draft pick, he jumped at the chance to meet longtime general manager and current senior adviser Billy Beane.Now, playing for the franchise that ushered sabermetrics into the mainstream, he is the embodiment of optimized offense. Kurtz, who set the walks record at Wake Forest University, leads the majors in walks (51) and on-base percentage (.448). During his on-base streak, he has batted .314 with a .468 OBP.