The Wayne County prosecutor's office said Tuesday there is "insufficient evidence" to persuade a jury beyond a reasonable doubt.
Police in Plymouth, a suburb west of Detroit, presented the case to prosecutors last week. A 22-year-old woman said she was assaulted early on Jan. 4 while attending a private party at the Ironwood Grill.
Police Chief Al Cox says a group of 10 Lions and support staff joined the party after finding that the restaurant was closed for regular business.
Cox says the decision not to file charges seems appropriate.