Daryl Morey has charts and spreadsheets and clever formulas for evaluating basketball players, and a degree from M.I.T. to make sense of it all. He would explain this mathematical wizardry, except that every few minutes his train of logical thought is interrupted by impulsive exclamations.

“Go, Rafer! All the way  nice!”

“Oh, jeez. After getting up this lead, we lost our minds!”

“Here we go, Luis! Here we go! Here we go!”

Morey, the rookie general manager of the Houston Rockets, is a wizard in the field of quantitative analysis, a friend of Billy Beane’s and a “Moneyball” true believer. He is the N.B.A.’s highest-ranking stat savant, the first mathematical magician to run a team.

Numbers are clearly very dear to Morey. Yet as he watched a recent game from a midlevel seat at Madison Square Garden, his refined logic was frequently overwhelmed by raw emotion. Morey became agitated when the Rockets took a bad shot. He bounced in his seat when they scored on the fast break.