Tracy Claeys was a defensive wizard. Jerry Kill liked to control the clock and squeeze teams into submission. Gophers fans knew their tendencies.

Right now, new coach P.J. Fleck is more of a mystery. He went 30-22 in four seasons at Western Michigan, earning a reputation as a terrific recruiter and master motivator. But for the general public, less is known about his fundamental football beliefs. Here are five things to know about Fleck’s football background:

1. Offense is his strength

Gophers offensive coordinator Kirk Ciarrocca, who held the same job under Fleck at Western Michigan, runs a one-back, one-tight end spread offense. WMU’s running backs thrived in the system. Quarterbacks need to make split-second decisions in the run-pass option, often throwing short passes and counting on receivers to produce yards after the catch.

“We ran the same offense last year, when we went 13-1, that we did when we went 1-11 [in 2013],” said former WMU quarterback Zach Terrell. “The system works, and if you trust the process and truly master what they give you, you can be as successful as you want to be.”

2. Defense is bigger question

Fleck chose not to bring Western’s defensive coordinator, Ed Pinkham, with him, instead going with former Arkansas DC Robb Smith. Arkansas’ defense got progressively worse under Smith the past three years, from 19.2 points allowed to 27.4 to 31.1.

Fleck prefers to run a 4-3 defense (four down linemen, three linebackers), but the Gophers are thin on the defensive line and strong at linebacker. Smith, like Gophers predecessor Jay Sawvel, plans to incorporate more 3-4 packages.

3. Played wide receiver

Fleck won back-to-back Illinois state high school championships at Sugar Grove Kaneland and set a state record as a senior with 95 catches for 1,548 yards and 16 touchdowns. He led Northern Illinois with 77 receptions for 1,028 yards as a senior. At 5-9, 190 pounds, he made the 49ers practice squad in 2004 and made his NFL debut in that season’s final game. He spent 2005 on injured reserve with a shoulder injury before retiring in 2006.

“He reminded me of some of those shorter slot receivers the Patriots have had [Wes Welker, Julian Edelman, Danny Amendola],” said Mike Nolan, who coached Fleck with the 49ers. “The thing that really stands out is their competitiveness. They know their jobs extremely well. They’re extremely smart, and they often outwit their opponents.”

4. Began as receivers coach

Fleck was a graduate assistant at Ohio State in 2006 before his former coach at Northern Illinois, Joe Novak, hired him as wide receivers coach. Fleck kept that job when NIU hired Jerry Kill and left in 2010 to join Greg Schiano’s staff at Rutgers. Two years later, Fleck followed Schiano to the Tampa Bay Buccaneers.

“We thought [Fleck] was just a big rah-rah guy, who could hoot and holler but maybe didn’t know football,” said Vincent Jackson, who had a career-high 1,384 receiving yards under Fleck. “No — P.J. is one of the smartest football coaches I’ve ever been around. He knows all aspects of the game.”

5. Stickler for fundamentals

As a player, Fleck wasn’t big enough to outmuscle defensive backs or fast enough to sprint by them.

“If you don’t have speed and size, you have to do everything else at an incredibly elite level, and you have to be consistent,” Fleck said. “So I developed my hands. I’d catch everything. I couldn’t create separation, but if the ball was thrown to me, I was going to catch it.”