In a small market, where rabid fans closely monitor players and coaches, the Fishbowl Factor for locally produced players is something BYU's Jimmer Fredette would face if the Jazz draft him Thursday night.
"He's much [better] than I ever was," said Roberts, another ex-BYU star. "Jimmer is going to be a high pick, so he'll feel pressure and expectations anywhere he goes. But in Utah, maybe it's more."
Mannion, who played against Roberts while attending Utah, claims the rivalry lingers when local players end up with the Jazz.
It's a phenomenon Fredette would experience if the Jazz take him with the No. 3 or No. 12 pick.
"It's different in this state," Mannion said. "When you go to the arena, they are all Jazz fans. But half of them are Utah fans and half of them are BYU fans. ...
"If the Jazz get Jimmer, there are going to be fans who love him but, just because he's a Cougar, there are some who won't at least right away."
Recalling the hostile reception he always received at the Marriott Center, Mannion laughed.
"It's just a Utah-BYU loyalty thing," he said. "You are always going to have fringe fans from both sides who are a little crazy.
"To them, it doesn't matter how good you are or if you're helping your team. They don't like you, just because you're a Cougar or a Ute."
The Jazz moved to Utah from New Orleans in 1979.
Over the next 32 years, nine players from local colleges played for them: four from Utah, three from BYU, one from Weber State and one from Utah Valley.
Rafael Araujo, the last Cougar to play for the Jazz, spent the 2006-07 season with them.
The Jazz's last Ute was Tom Chambers, who played for them from 1993-95.
"It puts a lot of pressure on the ballplayer," said Frank Layden, former Jazz coach, general manager and president.
"When he goes to church or out with friends, people feel close enough to ask, 'Why aren't you playing more? Why aren't you getting more shots?' That turns into pressure on the coach."
Looking back, Mannion understands the situation better than when he was a player seeking playing time from Layden.
"I was mediocre," he said. "... [But] you do have people on the street saying, 'You should be playing more. You deserve more time.' And, at the time, you agree with them because you aren't in the NBA because you think you're mediocre."
Said Roberts: "People would call me and ask about things like playing time. ... I can see how that element could add [pressure] to the situation."
Layden has seen Fredette play many times.
On Wednesday, he attended his workout at the Jazz practice facility, talked to Fredette and came away impressed.
Said Layden: "I got the idea this guy has a lot of self-confidence and would probably be very comfortable playing for the Jazz.
"It seems to me, he's a guy who performs best when there's a lot of pressure. ... Actually, I think he might thrive on playing here."
In Fredette, Layden saw a strong personality that could eventually win over Utah fans.
He compared Fredette to former BYU quarterback Jim McMahon.
"I think a lot of Utah fans actually admired and liked [McMahon]," Layden explained. "He had a toughness and a swagger about him that everybody liked. By the end of his career, I think Utah fans embraced him, whether they admit it or not."
Despite the risks that have surfaced in the past, the Jazz will take Fredette, if they think he is the best player available and can fill a role for them.
"In this day and age especially if you are a good player you've already had to deal with so much pressure and publicity," said general manager Kevin O'Connor.
"... We really don't care where guys come from, as long as they are good basketball players."