I'm creating this because it seems that people are missing some of the important facts that folks dug up and posted in the front page thread on this subject. (Mods, no hard feelings if you take this down.) I've done my best not to interject any opinion into what is below. My purpose in posting this is merely to try to have everyone on the same page as far as facts and timing.
2009 and earlier: OSCR investigates sexual assaults for U of M but only does so if the complaintant cooperates. They find someone guilty of sexual assault only if a "clear and convincing" burden of proof has been met.
Late Nov. 2009: The incident occurs. Police reports are made. Gibbons, of course, denies any wrong-doing...Not long after, Taylor Lewan allegedly threatens the young woman involved with rape if she presses forward. I have never been able to determine whether Lewan admitted to making this statement. Please let me know if you know otherwise...We don't know what happened internally to Lewan and Gibbons, but neither is suspended...EDIT: In fairness to Lewan, myself and others have inferred from a police report that Lewan was alleged to have threatened the young woman, but the police report in question is redacted as far as names (at least in the report available online).
Late 2009-Early 2010: The young woman decides she does not want to press charges, thereby ending the state's investigation. What OSCR does at this point is unclear.
2011: The federal government, via Title IX, tells universities that they must investigate alleged on-campus sexual assault regardless of the cooperation or lack thereof of the alleged victim. It also tells schools to use a "preponderance of the evidence" standard when evaluating guilt. http://www.michigandaily.com/news/university-adopts-new-sexual-misconduct-policy-0?page=0,0
Aug. 2011: U of M institutes an interim policy designed to comply with the new Title IX mandate. (See the link above.) It appears that the interim policy complied with the mandate to use the preponderance of the evidence standard and to investigate sexual assault claims regardless of cooperation from the alleged victim, but the university's online explanation of this is, in my opinion, somewhat unclear. http://studentsexualmisconductpolicy.umich.edu/faqs
The implementation of the interim policy appears to have led more women to come forward to make complaints, as the number of sexual assault complaints made on campus rose from three in 2010-2011 to 62 in 2011-2012. http://www.michigandaily.com/news/university-adopts-new-sexual-misconduct-policy-0?page=0,1
Aug. 8, 2013: The Washtenaw Watchdogs blog brings the Gibbons incident back into the public eye.
Aug. 19, 2013: U of M implements its current policy, described by the Daily as the result of a two-year fine-tuning process of the interim policy. (See all links above.) The current policy unquestionably calls for investigations of alleged sexual assaults regardless of cooperation from the alleged victim and unquestionably uses the "preponderance of the evidence" standard regarding guilt.
Nov. 20, 2013: OSCR produces a document telling Gibbons that a preponderance of evidence supports the claim that he committed sexual assault. http://www.michigandaily.com/sports/former-kicker-brendan-gibbons-expelled-sexual-misconduct
Nov. 23, 2013: Gibbons plays against Iowa.
Nov. 30, 2013: Gibbons does not play in the OSU game, purportedly because he is injured.
Dec. 4, 2013: Gibbons meets with OSCR to discuss the findings against him. (See last link.)
Dec. 16, 2013: Coach Hoke states that Gibbons may not play in the bowl game because of an injury.
Dec. 19, 2013: OSCR produces a letter telling Gibbons that he is expelled. http://www.michigandaily.com/sports/former-kicker-brendan-gibbons-expelled-sexual-misconduct
Dec. 23, 2013: Coach Hoke tells the media that Gibbons will miss the bowl game because of a "family matter."
A final note: Dave Ablauf, in the Daily article linked above (the last link), states that the AD cannot comment on the academics or university standing of an athlete. University spokesman Rick Fitzgerald also said in that article that he could not comment because of the Family Educational Rights and Privacy Act (FERPA). One could quibble a bit about what Ablauf and people in the AD can say about Gibbons if they wanted to test the bounds of FERPA, but there is little doubt that U of M's legal people believe exactly what Ablauf said, namely that he could not comment on the relevant issues. One errs on the side of caution in such circumstances...I point all of this out to say that Coach Hoke was never free to say that Gibbons was no longer at the school (save the unlikely event that Gibbons would have consented to this). I don't state that as a comment on what he did say.
EDIT: mackbru seemingly correctly points out that the school can at least arguably say whether someone is enrolled. See the link below that describes a FERPA exemption for "directory information." I highly doubt this covers saying that someone was expelled, but I am not a higher ed lawyer. There may be some big grey areas here, and none of this post should be taken as legal advice (sorry - had to say that).
Final final note: Credit to Don, Kilgore Trout, and guthrie for digging up much of what I posted above. Also thanks to those in this thread who have made suggestions.