Park remains on the team but will be inactive beginning with Saturday's game at No. 3 Oklahoma. The junior started Iowa State's first four games, completing 61.7 percent of his passes for 1,181 yards with nine touchdowns and five interceptions.
"Jacob is a great young man dealing with some personal medical concerns," Iowa State coach Matt Campbell said in a statement. "We are committed to helping him cope, supporting him on all levels and helping him prepare to get back on the playing field with his teammates as soon as possible."
There is no timeline for Park's return. Park, who began his career at Georgia before transferring to two small schools and eventually to Iowa State, threw three interceptions in the Cyclones' last game, a 17-7 home loss to Texas on Sept. 28. He appeared to argue with Campbell on the sideline during the second half but remained in the game.
Campbell denied rumors that Park had been suspended and reiterated his support for the quarterback earlier this week.
"We are focused on helping Jacob in any way we can," Campbell said in the Friday statement. "I know how important the football team is to Jacob and how important Jacob is to the football team. But, supporting one another in difficult times is where our focus is."