Shamrock Shuffle race officials were forcedSunday morning to call an audible on where the runners would run because a man was threatening to jump from the State Street bridge into the Chicago River. 

SWAT police officers were able to remove the man from his perch before the Shamrock Shuffle, a race expected to draw more than 40,000 participants, began, according to Chicago Police News Affairs. 

Police re-routed runners so that the bridge would not be part of the course. 

Now racers will go from Grand Avenue to Wabash instead of to State Street when they cross the river going North. They'll join up with Wacker Drive from there, as expected.