Because Nelson left school to serve an LDS Church mission after a promising freshman season, Aggie coach Brent Guy finds himself searching for a No. 1 quarterback.

When Utah State opened preseason practice Tuesday, three players crouched at the starting line to begin the race for the top job: senior Leon Jackson III, junior college transfer Sean Setzer and sophomore Jase McCormick.

Jackson and Setzer are the favorites, according to Guy, while McCormick is the long shot.

"We are constantly evaluating those guys - every day, in every practice - because that position is so important to the offense," Guy said.

Utah State's starting quarterback will be the one who is "consistent, makes good decisions and doesn't make that big mistake. . . . We're looking for the guy who can move the team, who can make first downs and get us some points," Guy said.

Jackson is the only quarterback with Division I experience. He started nine games as a sophomore and the first five games last season before being replaced by Nelson.

"Leon's strength is having played in a lot of games," Guy said. "He has started and won games at Utah State. He's got experience on his side."

Jackson hopes to reclaim the No. 1 job while learning a system imported by new offensive coordinator Darrell Dickey.

Noting that Dickey is his fourth offensive coordinator since 2004, Jackson said, "Every year, I've been competing for a spot, so this is nothing new. [But] I have confidence in my ability. I know I'm going to go out and have a great year."

Asked if Dickey's system is conducive to his success, Jackson said, "It's the best one, in terms of the quarterback. Everything seems good right now."

Jackson's immediate goal is "to get better, as far as learning the system, and to become more sound with my techniques." His long-term goal is to "lead our team to a bowl game."

According to Guy, Setzer's strengths are his competitiveness, his arm strength and his size. He stands 6-foot-2 and weighs 231 pounds.

Said Guy: "He's a big, physical guy. He has the durability to take some hits, which our quarterbacks must do. . . . For Sean, it's mostly a matter of catching up," learning the system and adjusting to the speed of Division I football.

In all, 105 players reported for the opening of preseason drills, including 88 who participated in spring practice and 19 starters from a year ago.

"We are excited about that experience," Guy said.

On defense, Utah State returns 18 players who started at least three games last season, including linebackers Jake Hutton and Paul Igboeli.

Hutton, injured most of last season, was a freshman All-American two years ago. Forced onto the field by Hutton's injury, Igboeli developed so quickly that he became the Western Athletic Conference Freshman of the Year.

Also in camp are 32 freshmen, including 17 scholarship players.

"There are a few that we will look to have an immediate impact," Guy said

Utah State begins two-a-day sessions Monday. The Aggies' first scrimmage is Aug. 16.

luhm@sltrib.com