In a statement, the athletic department said it was aware of the arrest and will continue to gather the facts, but Allen's suspension takes effect immediately.
The Bloomington Herald-Times reported that the Indianapolis native faces preliminary charges on two counts of dealing methamphetamine, two counts of dealing heroin and one count of dealing cocaine following an investigation by the Indiana State Police.
The newspaper said Allen also is also charged with possessing cocaine, more than 10 grams of heroin, and maintaining a common nuisance.
The junior led the Hoosiers with 74 tackles last season. He also had 3 1/2 tackles for loss, one sack and two interceptions.