‘Moneyball’ questioned first base’s challenges. Some Orioles are learning the position is ‘unlike any other.’

One of the most intriguing competitions at Orioles spring training is among the left-handed hitters vying to be Ryan Mountcastle’s backup first baseman.

The team compiled a group of these players with major league experience — including Ryan O’Hearn, Franchy Cordero, Josh Lester and Lewin Díaz — and invited them to spring training as nonroster invitees to compete for that spot.

But will that seat on the bench even exist come opening day Thursday in Boston?

The answer to that...