Spanarkel came to Duke in large part because Bill Foster told him he would let him play baseball.
Remember Quinton McCracken? DB for Steve Spurrier, baseball star, long MLB career. He's currently a coach with the Durham Bulls.
Back in the old days, before sports became more specialized, Duke (and other schools) had lots of multi-sports stars, Dick Groat, Bill Weber, Ace Parker, George McAfee, Eric Tipton, Gordon Carver, Bob Gantt, Ed Koffenberger, Dave Sime, many, many more. Bobby Brower went from Duke running back to MLB outfielder. Don Altman quarterbacked Duke in the 1960/61 Cotton Bowl and a few months later pitched for Duke in the College World Series.
It's a lot harder to do these days. Johnathan Lloyd played a full season of baseball at Duke but dropped the sport early in his sophomore season. Too much overlap with fall baseball and spring football hurt his development in both sports and on the diamond he was competing against guys who played baseball at a high level for 12 months a year, which he could not do.