"You had a couple sick games last year," the fan said, rapid-fire. "You tore it up. ... You have to be feeling pretty confident about it."
Riley listened patiently, an amused look on his face, then responded.
"That's just the way I am," Riley told the fan.
Confidence has never been an issue for Riley. Not when he was growing up in Oregon as the youngest of four siblings and the son of a high school football coach. And certainly not now when he's trying to unseat Nate Longshore as Cal's starting quarterback.
No one knows which quarterback -- Brock Mansion is also in the running but a long shot -- will ultimately win the job. That's up to coach Jeff Tedford, and he said he probably won't decide until the week of Cal's Aug. 30 season opener against Michigan State.
But I'd give Riley the early edge in this competition, largely because of the aggressive, confident approach he's taking.
Consider what he told our Jonathan Okanes before spring practice began.
"I'm going to have the attitude that I'm going to be the man," Riley said. "I want to be the guy. I want everybody on the team to want me to be the guy, and not leave any doubt. I want to make sure they want me in the game and they trust me."
If I'm a coach, that's the attitude I'm looking for from my quarterback. Not arrogant or cocky, but confident, passionate and competitive. A leader.
You can't question Longshore's intelligence, experience or NFL-caliber throwing arm -- he threw for more than 3,000 yards in 2006 and has 26 starts to Riley's one.
But you can question his mobility and durability -- he's sidelined now with an injured right pectoral muscle. And, more importantly, you can question the way he's approaching the competition for his starting job.
"I'm just trying to get better," Longshore said before spring practice began. "I'm not worried about beating any other quarterback. I'm out there to beat the defense. ...
"If I put everything I have forward and I improve, no matter what happens, I'll be happy with myself. I'll be able to look myself in the mirror and know I did everything I could."
When athletes start talking about being happy when they look in the mirror, that's usually when they sense their starting job or, in the pros, very career is in serious jeopardy.
I can't imagine Riley being happy in any sense if he loses this competition, no matter how much he improves or how well he plays in spring ball and training camp.
Riley said Saturday that his competitive nature stems from his battles with two older brothers -- one is nine years older, the other eight -- and a sister who is just a year older but is "probably the best athlete in the family" and used to beat him up.
"They'd always talk down to me," Riley said. "And I'd always go, 'Be ready. I'm going to beat you guys someday soon.' It always carried with me. I think it's just the type of person I am. I don't want to lose."
By most reports, Longshore was having an impressive spring before being injured. But Riley was even more impressive during Cal's 42-36 victory over Air Force in the Armed Forces Bowl in December.
Riley came off the bench in relief of Longshore with the Bears trailing 21-0. He completed 16 of 19 passes for 269 yards and three touchdowns and ran for a score. He led the Bears to touchdowns on his first six drives, showing the poise and leadership of a veteran.
Many Old Blues thought, and rightfully so, that Tedford should have turned to Riley much earlier in the season when Longshore was battling a sprained ankle and the Bears' season was imploding.
After his performance against Air Force, Riley is now clearly the people's choice -- at least most of the people -- to be Cal's starting quarterback. When Riley's name was announced before the scrimmage's first series, fans applauded loudly.
"It definitely is a little awkward, but I'm excited that people like me," Riley said. "I just have to work hard. It's not really what the fans want. I love fans, but it's really what the coaches want."
Longshore has the edge in college experience, but Riley is wise beyond his football years. Long before he reached high school, Riley watched countless hours of game tapes with his dad, Faustin Riley, his coach at Beaverton High School. He received a priceless football education.
But Riley said that once he entered high school, his dad showed him no favoritism. Quite the opposite.
"My dad was always toughest on me," Riley said. "He wasn't really like a dad-coach."
Approaching his junior season, Riley thought he had the starting job locked up. But his dad made him compete for the job with a sophomore.
Riley won that job, and now he's confidently taking aim at another.
Contact Eric Gilmore at email@example.com.