This approach differs radically from the high-mileage, high-intensity philosophy of Michael Phelps's coach, Bob Bowman.

WSJ: Missy Franklin: How Not to Ruin a Swimming Prodigy

"Their fantasy players are a different ilk than the more general fantasy player, " said Bob Bowman, chief executive of MLB Advanced Media.

WSJ: CBS Opens Sports Site to Fantasy App Makers

In the last year, Major League Baseball's Internet company MLB.com nearly doubled the number of mobile engineers it has to 19, said MLB.com CEO Bob Bowman.

WSJ: Mobile App Talent Pool Is Shallow