He just got married to his long-time girlfriend this past March and in June announced that his wife is expecting a baby. She was captain of the gymnastic team at Stanford and graduated with a degree in architectural design, the same degree Luck has. I'm thinking that he's had a change in priorities and along with the pain he's endured for the past 4 years, he decided to quit now. Colts fans are upset (I read they booed Luck off the field) and although I can empathize with their disappointment, I don't think anyone has the right to fault someone else for making what they feel is the right decision for themselves and their family.
I wish him LUCK in whatever he chooses to do with the rest of his life.