They've also had to scratch and claw their way past other, often more expensive players for a chance to be seen on the big league stage.
Theriot (at least as far as the immediate future is concerned) secured his spot on the Cubs' 25-man roster early in spring camp this year when Cubs manager Lou Piniella informed the scrappy middle infielder that he'd break with the team and head north to Cincinnati for Opening Day.
Theriot rewarded Piniella by batting .299 with the club in April.
During that time, Fontenot found himself back in Triple-A for a fourth consecutive season, poised to reach the same level of play in perhaps the same manner as his former LSU teammate.
"Just like Ryan did, the first thing you have to do is make it as a utility guy," explains Cubs Minor League Infield Coordinator Bobby Dickerson, who tutored both Fontenot and Theriot in his tenure as a minor league manager in the organization before taking on his current role.
"You have to show you can play, and then go steal somebody's job."
Fontenot has shown he can do the first part well.
He entered the 2007 season a career .287 hitter in 606 minor league games and had advanced to the ranks of Triple-A with the Ottawa Lynx by only his third season since being tabbed by the Baltimore Orioles in the first-round of the 2001 draft. Then in February, 2005, he was traded to the Cubs as part of a blockbuster deal that sent Sammy Sosa to Baltimore.
After posting respectable if not above average numbers with Triple-A Iowa in both 2005 and '06 with the Cubs, Fontenot was batting .340 through 54 games with the team prior to being called up to Chicago on June 9 (the date of his 27th birthday).
As Dickerson and others are quick to point out, hitting has never presented a real problem for Fontenot.
But defensively, things haven't always been so simplistic.
Fontenot committed 43 errors combined as part of his learning curve in his first two seasons in the Orioles' farm system at second base – a position he has played regularly since his prep days at Salmen High School in Slidell, La.
Since then, Fontenot has gradually reduced the number of miscues from year to year, having also flashed some versatility. The past two-plus years, he's added third base, shortstop and the outfield to his growing list of positions.
"The main thing is I've felt comfortable everywhere I've been," Fontenot says of his improvement with the glove. "I've taken the attitude that groundballs come at you pretty much the same way."
A combination of Fontenot's versatility, his improvement with the glove, continued hitting and high on-base totals has finally put him in a major league setting with the Cubs. The question is, for how long?
Fontenot believes he can make it a one-way trip.
"That's the main goal," he said. "You have to keep playing, stay healthy, and put up numbers and play hard every day, [but] I've been getting some good swings on the ball. I try to stay compact, take it easy, keep it simple and have a short swing. The key is getting good pitches to hit and putting a good swing on them."
Fontenot has shown he can do that. But is it enough, and if not, what else does he need to do?
"Just what he's doing now," Dickerson readily replies. "He's showing he can play multiple positions and showing that he can play the left side of the diamond, which is the key to being a good utility guy. We all know he can hit, what he did at LSU and what he's done his whole minor league career. Now he's showing his defense is there as well."
"He's on a mission," said Dickerson.
Just like Theriot.