SCOTTSDALE, Ariz.

When Brandon McCarthy signed with the Arizona Diamondbacks in December, he did not dwell on their master plan. McCarthy, a starting pitcher, considered factors that would not change: the city, the contract and so on. Trusting a team’s blueprint seemed foolish in a sport so filled with surprises.

“Predicting anything in baseball is dumb and never seems to work, but especially this division,” McCarthy said. “You just throw your hands up. This is more sit-down-and-watch as opposed to trying to figure out what’s going to happen.”

As a player, McCarthy has the luxury of controlling at least a small part of the outcome. The general manager of the Diamondbacks, Kevin Towers, projects performance for a living. His first two seasons here confounded him.

Inheriting a last-place team after 2010, Towers said he expected about 84 wins. The Diamondbacks surprised him and won the National League West. Last season, Towers expected the team to be better. It sank to .500.