Why Petersen finally left Boise State

— -- Chris Petersen did what few thought anyone would ever do at Boise State. Not only did he take the Broncos to two BCS bowls and win nearly nine of every 10 games he coached, he stayed for eight seasons. Petersen ended that era Thursday night, signing a term sheet to become coach of the Washington Huskies.

Under Petersen, Boise State became a household name in college football. Yet he resisted the urge to climb to the next rung. Instead, he took his program to unprecedented heights. Even with this season's 8-4 record, the first year that Petersen failed to win 10 games with the Broncos, his record is 92-12 (.885). That ranks first among FBS head coaches with at least five years on the sidelines.

If Petersen never won again, he will be glorified in the history of the game for leading Boise State to victories in the Fiesta Bowl in the 2006 and 2009 seasons. The first one, a 43-42 overtime upset of Oklahoma in which the Broncos executed one trick play after another to win, made Boise State America's darlings and ranks among the top games of the past decade. In the second, a 17-10 defeat of TCU, a fake punt led to the Broncos' winning touchdown in the fourth quarter.

As Petersen took the Broncos where no one believed they could get -- or thought they belonged -- he flirted with nearly every prominent university on the West Coast. Stanford and UCLA both talked with him. Before this year, he always stayed. But clearly Petersen had decided the time had come to leave. Petersen pursued the USC job, and when he didn't get it, quickly replaced Steve Sarkisian, the coach who did.

Petersen left for a number of reasons:

• The transition from the BCS to the College Football Playoff will make it more difficult for programs such as Boise State to reach the top of the sport.

• As he continued to stay at Boise State, and the Broncos continued to average 12 wins a season, a small program with limited resources strained to keep him. During Petersen's tenure, Boise State expanded Bronco Stadium from 30,000 to 37,000 seats, which is still only the 84th biggest in the nation. Yet Petersen made $2.1 million this season, and the disparity between his salary and his environs gnawed at him.

• His older son Jack is now in college. His younger son Sam, whose health issues as a small boy helped keep Petersen in Boise, not only fully recovered, but will start high school next year. It's a good time to make the transition.

Petersen and Boise State prided themselves on finding players rejected by other FBS staffs and molding them into stars. When Idaho State backed off Ryan Clady, Petersen signed him and turned him an All-American offensive tackle and a first-round draft pick. Quarterback Kellen Moore chose Boise State over FCS Eastern Washington. Moore went 50-3 as a starter for the Broncos, the most victories by any quarterback in FBS history.

Moore is from Prosser, a small town in Washington wine country. The Huskies never showed much interest in him. In 2008, the season that Moore, a redshirt freshman, led Boise State to a 12-0 regular-season record, Washington went 0-12.

"We need that same blue-collar, tough kid that loves football and is a good player," Petersen once said. He looked for the toughness, and if he got the size and speed, great. Boise State didn't get the tough kid with size and speed. He signs with the Washingtons of the world, which will make Petersen's transition from have-not to have an interesting one to watch.