Ohio State has been favored in its past 51 games, the longest such streak in the nation and one that dates back to the 2015 College Football Playoff championship.
That streak will likely end this week.
The sportsbook at Caesars Palace in Las Vegas on Sunday installed the Buckeyes as 3.5-point underdogs against Michigan. Ohio State hosts the Wolverines on Saturday in a showdown that will decide the Big Ten East champion.
Barring dramatic line movement this week, the Wolverines will be favored over Ohio State for the first time since 2011, when Michigan knocked off the Buckeyes 40-34 as 8-point favorites. It was the Wolverines' last win in the series.
Ohio State has won 13 of the past 14 meetings against Michigan, which hasn't won in Columbus since 2000.
The Buckeyes' 42-20 win over Oregon in the inaugural College Football Playoff marks the last time they entered a game as underdogs (6.5 points).
If the line holds, Saturday will mark only the seventh time the Buckeyes have been underdogs under coach Urban Meyer. They won the previous six games straight up.
It also would be the first time the Buckeyes have been home underdogs in Meyer's seven seasons. The last time a Meyer-coached team was a home underdog was in 2003, when he was at Utah, according to ESPN Stats & Information.
Prior to this season, Las Vegas sportsbooks had the Buckeyes listed as 9-point favorites over the Wolverines. Michigan has appeared to be the better team, though, and is riding a 10-game winning streak.
Alabama, which opened as a 24-point favorite in this week's Iron Bowl against Auburn, marking the 51st consecutive game it will be favored, would hold the longest active streak should the Buckeyes' streak end this week. The Crimson Tide have been favored in 123 of their past 124 games overall. Alabama was a consensus 1-point underdog at Georgia in 2015.