Well there's really no way to answer the question since we can't with any degree of certainty know the velocity of the football, the location of the guy throwing it and where Flash starts off relative to them.
Generally speaking I'd say Flash just has to run the distance from his starting point to the location of the thrower give or take a few micrometers since there's no way a football can ever reach speeds where it could give the Flash a serious challenge.
__________________
“Where the longleaf pines are whispering
to him who loved them so.
Where the faint murmurs now dwindling
echo o’er tide and shore."
-A Grave Epitaph in Santa Rosa County, Florida; I wish I could remember the man's name.
As soon as the ball leaves their hand. I don't think Anyone can throw a ball at light speed or above here. He might have to speed steal the ball so that it doesn't blow right threw his hands and body.
At a strong enough throw the football will break escape velocity and head into space... Remembering the curvature of the earth either the ball breaks escape velocity or if it is just short then the ball will eventually fall back down to earth... I forget the exact math... Of course if the ball falls into orbit around earth flash is also screwed.... And if captain america can nail planes a mile up with a twenty lb shield im gonna say comic book physics says spiderman level and up can make a football go orbital
__________________ Quotes from Hia8:
"I claimed that the science is sometimes faulty."
"You don't understand. This is fiction. That means none of this stuff really happened."
"There is no writer to purposely ignore a character's natural ability just because it suits the story."
"in some cases because the writer knows that Character A will dominate Character B easily and refuses to allow this to happen for the sake of the story."
Flash is playing the role of a wide receiver here obviously...
Unless of course you believe they are treating flash as a running back and passin off the ball....
And yes while flash is fast enough to get to the quarterbacks hands and grab the ball
Midair inches away if even that fron a quarterback once he has released it... I think the intent is on some sort of hail mary play
__________________ Quotes from Hia8:
"I claimed that the science is sometimes faulty."
"You don't understand. This is fiction. That means none of this stuff really happened."
"There is no writer to purposely ignore a character's natural ability just because it suits the story."
"in some cases because the writer knows that Character A will dominate Character B easily and refuses to allow this to happen for the sake of the story."