Maty Mauk instead will likely make his first collegiate start for the 14th-ranked Tigers, who will try to match their best start in the past 53 seasons in Saturday's visit from No. 22 Florida.
Missouri earned three victories in its first nine SEC games - all against teams with lackluster records - before a 41-26 upset at then-No. 7 Georgia this past week. The celebration of that win, however, was marred by Franklin's right shoulder injury in the fourth quarter.
The senior, who was third in the conference in total offense, is expected to miss at least three to five weeks. That will likely keep him out for a three-game home stretch that includes a matchup with No. 11 South Carolina next weekend.
"It's a good thing it's a team sport," Franklin said. "It stinks that I went down but we still have a lot of talent. I know that we can do it."
The job of keeping the Tigers (6-0, 2-0) unbeaten will fall to the freshman Mauk, who left high school as the nation's all-time leading passer after surpassing his older brother Ben's mark. Missouri has started 7-0 only once since 1960, accomplishing the feat in 2010 after upsetting then-No. 3 Oklahoma.
"(I've told him) just to trust your preparation, that you have good people around you and to just go play," coach Gary Pinkel said. "In high school, he was the guy that played at the really high level for a lot of people and had lots of success.
"This is certainly a lot different. Quarterbacks have success for certain reasons. Some of the things that is important to them to have poise, and poise under pressure. He is going to be nervous, but he will do fine."
Mauk, who has appeared in three games this season, will face one of the nation's top-ranked defenses. Florida (4-2, 3-1) is in the top five among FBS teams with averages of 13.0 points, 235.3 yards and 152.0 passing yards allowed.
The Gators held then-No. 10 LSU nearly 29 points below its season average this past weekend but couldn't generate enough on the other side of the ball in a 17-6 road defeat. Florida also suffered another major injury when second-leading rusher Matt Jones was lost for the season because of a torn meniscus in his left knee.
"To have this setback is disheartening for all of us," coach Will Muschamp said. "We'll get the next guy up. We've recruited well at the position, so those guys will get their opportunity and they need to be ready to go in all situations."
The short-handed Gators will try to overcome Jones' absence by duplicating their performance in last season's visit from Missouri, a 14-7 win Nov. 3. Florida, ranked No. 8 at the time, got four interceptions off Franklin, including one that set up the go-ahead touchdown with 13:32 remaining.
Aside from Franklin's injury and cornerback E.J. Gaines' questionable status, the Tigers will be much healthier than in last year's meeting, especially on the offensive line. With stability on that front, Missouri is eighth in the nation with 45.7 points per game, and its 515.7-yard average ranks 12th.
The Tigers also failed to record a sack in last season's matchup but enter this game with 17, the second-highest total in the conference. Michael Sam is tied for the SEC lead with six sacks and has a conference-best 10 tackles for loss.
"Certainly, they're playing very well. Last year they had a bunch of injuries on the offensive side of the ball," Muschamp said. "They're a team that's very explosive and it catches your attention when you turn on the tape on both sides of the ball."
This marks Florida's first trip to Missouri. The first of the schools' two previous matchups took place at the 1966 Sugar Bowl, a 20-18 win for the Tigers.