Columbia police records show the 20-year-old sophomore was cited about 1:40 a.m. Friday with possessing 35 grams or less of marijuana.
Penton also was among four Missouri athletes arrested on suspicion of marijuana possession in March.
School spokesman Chad Moller says Penton, who has started all nine games this season, is suspended indefinitely.
Missouri has a bye this week. It isn't clear whether the St. Louis native will play against Texas A&M on Nov. 15.
Penton doesn't have a listed phone number, and didn't immediately respond to an email message Saturday from The Associated Press.