The rising fifth-year senior, with his family, released a statement to CougarsDen.com saying he will not return to the team for his final season and will explore his options, whether at another school or possibly in the NFL supplemental draft.
The reason for his departure is unknown.
"It is with regret and deep humbling that I am ending my playing career at the University of Houston," Sims' statement read. "I have a lot of great memories that I will carry with me forever. I want to thank the University of Houston for allowing the opportunity to be a part of its football program. I have worked extremely hard while I have been here at U of H and made every attempt to carry myself in a manner that would reflect the utmost integrity upon the school and this program.
"I don't know what my next step will be. I have one more year of eligibility, therefore I may look to play (1) more year of college football or I may enter the NFL Supplemental Draft later this year. My family and I will continue to discuss my options and we will make a decision in the near future."
Sims has 384 career carries for 2,370 yards and 29 touchdowns, and 158 career catches for 1,707 yards and eight more scores.
The school released a statement Wednesday night saying Sims was weighing his future.
"We congratulate Charles on receiving his degree [in health] last week and becoming a Cougar for life. He has been a leader for our program both on and off the field with a number of accomplishments," Houston coach Tony Levine said.