Donovan McNabb -- Arrested for DUI In AZ ... Again

Ex-NFL QB Donovan McNabb was popped for DUI in Arizona on June 28th ... the second time he's been arrested for DUI in 2 years.

The Gilbert Police Department says McNabb rear-ended a car that was stopped at a red light around 11:35 PM -- and when cops arrived to the scene, they determined Donovan was drunk.

The 38-year-old was subsequently arrested for DUI and transported to a nearby police station where he was booked, cited and eventually released.

As we previously reported, McNabb was arrested in December 2013 after cops say he was speeding in Maricopa County around 3 AM. He served 1 day in an AZ jail.

As for what McNabb is facing ... we spoke with John Kelly, a DUI attorney in Arizona, who tells us Donovan is realistically looking at 9 to 10 days in jail if convicted of a normal DUI (the punishment could get a lot worse if his blood alcohol level was "extreme").

Kelly says it's also common for people convicted of a 2nd DUI to have a ignition interlock system put in their car, which requires a breathalyzer test before the user can turn on the vehicle.

In addition, Kelly says McNabb will also face court fines in the $3,000 to $5,000 range.