Years ago, Josh Brown had perhaps the most simple and underrated job within the Cal Poly football program.

He was a ball boy.

This was back when his father-in-law, Mike Church, served as assistant coach for the Mustangs.

But now, Brown has a much more important job. Cal Poly announced Monday his promotion from special teams coordinator and inside linebackers coach for the past two seasons to the team’s new defensive coordinator — replacing Greg Lupfer, who resigned last month to become the defensive line coach at Colorado State.

Brown, 35, was the ideal candidate thanks to his familiarity with the Mustangs and the fact that the first day of spring practice starts Wednesday morning.

“Anytime you have 10 to 11 days before you start spring (practice), I definitely shrunk the pool, so to speak,” Cal Poly coach Tim Walsh said about the hiring process. “But I did have a couple of young people that I coached with before that I talked to. Talking with Josh, I thought the most important thing was going to be terminology turnover, even though we already decided that we were going to change some things and how we packaged some things on defense and now probably even restructure a little bit more in the summer.

“But going in with a base defense that we kind of believe in and think we can do well, I think Josh made sense in the interview.”

Brown plans to keep the Mustangs defensive scheme “simple.” He wants his defenders to be fast, stop the run, force turnovers and compete for the ball. He knows the defense will have to adjust to not having All-American cornerback Asa Jackson, a potential mid-round selection in the NFL Draft starting April 26.

Brown did mention at his press conference Monday the names of defensive backs Alex Hubbard and Matthew Reza to be very important pieces to his schemes in the upcoming season.

“It’s going to be similar to what we’ve done here in the past,” Brown said. “It’s going to be a lot simpler, though. One of the issues that we felt as a defensive staff last year, and even though Coach Lupfer was here evaluating the previous season, was that our guys weren’t playing very fast. Some of it was due to too much scheme and some of it was because of them not picking up a scheme. Our main goal is going to be simple: play fast.”

Brown is a 1994 San Luis Obispo High graduate who returned to the Tigers as a linebackers coach and helped the program to a 12-2 record and a CIF-Southern Section runner-up finish in 1998.

“(Brown) always wanted to be a college coach,” said Vic Ecklund, the former San Luis Obispo football coach who is now the school’s athletic director. “He helped us out and did a great job, loved the game and put all the time into it that needed to be done.”

Brown was a graduate assistant at Arizona State in 2006 and an assistant at Foothill College from 2000-05. He was also an assistant at Gavilan College in 1999, which was the school he played at for two seasons before playing one year at Oklahoma.

After graduating from San Jose State in 2003, he went on to coach linebackers and become a recruiting coordinator at Sacramento State, helping the Hornets post their first six-win season in 15 years in 2008. Brown spent the following season at Kansas, working directly with the linebackers.

Two years ago, Brown said being hired onto the Cal Poly coaching staff “was a big highlight in my life.” He was back in a place where he grew up, made friends and became a ball boy for the Mustangs. Now, Brown has a bigger role.

“This is like the icing on top of the cake, becoming the defensive coordinator and getting promoted and showing really what I can do,” he said.

Tribune reporter Joshua D. Scroggin contributed to this report.