Missouri offensive coordinator David Yost resigned Monday, the school said in a statement.
Yost, citing personal reasons, said he felt it was the right time to leave.
"There are a lot of factors that played into the process of coming to my decision," Yost said. "I feel like I've had a great run here and that it's just the right time to turn it over to someone else. On one hand, it's a really hard decision to make, but on the other hand, I feel good that it's the right decision at the right time for me."
Yost has been at Missouri since Gary Pinkel became head coach in 2001. He was an assistant with Pinkel at Toledo from 1996-2000.
"It is very difficult to imagine not having David as part of our staff," Pinkel said. "I asked him to reconsider, but I respect his decision. He has been such an instrumental part of our program and everything we've built since we came here. There's hardly an aspect of our program that he hasn't had a hand in, and we're going to miss his leadership and energy.
There is no timetable for naming his replacement.