Diehl, who is of Croatian descent, admitted to a police officer that he had been out drinking while watching a UEFA Euro 2012 soccer game in which Croatia beat Ireland.
Diehl blew a .182, which is double the legal limit. He was arraigned on Monday and released after being charged with two counts of operating a motor vehicle while under the influence of alcohol or drugs. If convicted Diehl could potentially be sentenced to one year in jail and/or a $1,000 fine.
Diehl is due in court on July 26, which is also the first day of New York's training camp.
Diehl has started every game he has appeared in for the New York Giants during his nine-year career, except for four games he missed in the 2010 season because of a hamstring and hip injury.
The NFL and NFL Players Association are expected to continue to look at increased discipline for driving-under-the-influence, a source with knowledge of the situation told NFL Network's Albert Breer on Tuesday.
The current policy states a first DUI results in a fine of a game check, up to a maximum of $50,000, with subsequent violation leading to further discipline, which can include suspensions.